One thing is to be kept in mind. The design life of passenger car is 7 years (source). Mostly the car can give you longer service life even if poorly kept, but take note: after the design life, nothing happens to the mechanicals. They can always be replaced. The main problem is that the structure becomes weak. This results in all sorts of issues such as the holders for mechanical parts not being in place (resulting in greater wear), greater chassis flex contributing to poor handling and as a result increased driver fatigue, making the roads overall more hazardous.As per my previous experience (kept many old cars), your problems cannot be solved by spending ANY amount of money on the car. It has served its useful life and for the betterment of the society it should be taken off the roads. But since here there is no fitness standard and ever decreasing purchasing power, most people are forced to keep using out of date and unfit vehicles. [Ever notice how developed countries like Japan and England force older cars off the road by increasing tax/insurance on older vehicles or by simply conducting roadworthiness (fitness) tests. This way their entire society is able to benefit from the improvements in e.g stopping distance, driver & passenger comfort, lighting, fuel economy etc. whereas us people are seeing the same Mazda 323 black taxi our entire lives.] Unfortunately, many people here face the same dilemma.Now we see one by one:
Tip: Repair only as much as barely necessary. Old car is like a grave. No matter how much you invest into it no life will come out of it. Performance upgrade as you say is done to something which is already in pristine condition. E.g you buy a new car and fit it with chassis stiffeners etc. An old car will neither go to zero-meter condition neither better than that (unless it is a classic and one would be willing to invest too much for it). I have many bitter experiences of my own. That's why telling you this.
Mainly because the chassis has grown weaker. The strut tower mount and control arm mount (mukki) are not in their place. This is incurable. (I mean you can cure it but you should spend on the car considering its market value).
Again, this cannot be repaired unless you go for it on a time-to-time basis. Since the entire chassis has grown weak, once you strengthen one part by superimposing additional metal over it, it will immediately begin to crack in another place. Just have a little repair done whenever the need arises. Trying to get it done all in one go would not only go futile, it will also give the impression to the denter that you are an easy customer. This way he/she will start charging you more (which you won't want to happen at all). Again, as much repair as needed.
I faced the same problem. Many denters told me the mukkian are not in place. Many told me they are. The repair system in Pakistan means that there are no drawings, diagram or any other thing to refer from. How do they say it is not in place? Do they measure it? If they measure it what is the standard? Most of the time it is just a ploy to create more FUD and extract some money out of you. In my case, I went to a fellow Pakwheeler and we measured his car which had never been repaired in this region and found out that the centre-to-centre between bolt to bolt was 4 mm off. Means my car was measuring 742 mm and his was 738 mm.
Front girder (locally called gatri) is usually the first to rust (if the rear wheel arches don't happen before it) because of leaking radiator. Most of the times the replacement 'gatri' is not fitted in the proper manner, and the fitting of engine mount becomes off by ~2 mm or so, which is enough to cause premature wear of engine foundations in already rough 3-cyl engines. Given that as time passes, the mounts you can buy get poorer and poorer in quality, you see bills running up.
Again, spending this much on old cars is never justified. No matter how much you spend on this vehicle now, it will never restore to what it was like in 1997
The springs you bought are not perfectly agreeing with each other nor with the car. Rather than buying springs on the basis of specification (free length and spring rate), here we buy them like this: 5-kari, 6-kari, 7-kari, gari kitni oonchi karni hai ji? Even if on the packing of springs all these parameters are mentioned (if you buy branded BDL springs from Kashmir automobile in Plaza - they have a branch in Lahore too, they have all this info for all models of their springs), you never know what spec to get for your car because the culture is to depend upon ustaads rather than repair manuals. You can never find a repair manual for any car. And most of our cars aren't even contemporary so no luck on the internet also.Also, there is a lot of chassis flex. Khyber and Cultus lack much chassis rigidity by design. Add the effects of ultra thin (read: out of spec) material our local assemblers use, 300k km of bumping in potholes and patchwork repair by local ustaad denters with steel sheet of specification unknown, the car is flexing like an old charpoy.
To cut it short,1) the mukkian/gatri etc. will never come in perfect alignment. Why? Because there is no reference you can compare to. How will you know they are in line in the first place?2) Do not change the wheel hubs or the other many things you mentioned. It will be a waste of money with little improvement. Only replace something if it is really worn out.Once you say you have everything new. Next you say it needs a suspension job. What does this mean? The photographs show that body work indeed needs to be done. I'll PM you contacts of one or two denters for this.Now repair work that you say arises for you in 2-3 weeks. Given you've driven your car 300k km in 15 years, means that your weekly running is about 385 km. This means you lose the settings in 1000 km. It could depend on your driving style (older cars should be driven much more carefully) and also may be the others you are referencing drive 1000 km in 6 months (you never know).Again, just like all other Pakistanis, you are also having difficulty upgrading to a more recent car. You could sell this one and use the amount for down payment of a cultus or the new EFI mehran. You will not save any money if you keep spending on this car like you intend to. Even if you spend gazillions on it, it will still remain beat up. Repeat: Just get the bare minimum done to it, this way you'll save the money which would come in useful in buying a more recent car.Sorry for disappointing you, but the time has come to move on. Save your money towards the future instead of focusing on something by-gone.EDIT: An example for the underbody brace can be found here: Suzuki Swift (1989 - 1994) Front Lower Bar / Front Member Brace - Ultra Racing Product Catalog. It is currently in fashion here and any good denter would make it for you in PKR 800-1200 out of GI (plumbing) pipe. If you want it done, ask the denter not to weld it but make it with adapters so that it can be tightened through nut bolt. The same bolts that keep the control arms in place should be used in this case. This tube brace may be a good idea in places where there are superb roads but not here. If the brace becomes entangled in some hump or raised manhole cover it could not only give you a big bodywork bill but God-forbid may also prove deadly. A year ago I was in same woes and discussed it a lot with @Xulfiqar and @nfssaad but in the end decided against it. (The brace @Xulfiqar was talking about in post # 1817 is a little different but I am sure other parts of the floor of your car are in a similar state, and anything which can tear through the floor and possibly impale the occupants is not advisable at all).
