To my knowledge using spacers or using springs from other cars are both not a good idea,
I have heard that spacers screw up the suspension and its better to use the same thickness in slightly longer springs,
I experimented with spacers and using some other cars springs on my jeep which has a 4 springs 4 shocks suspension,
the spacers felt like someone swung a bat at the suspension every time it went over a bump and the springs experiement was horrible too, the car came crashing down and the springs made a nasty noise like karang karang, sounding like the springs metal was in a lot of pain,
I then found out about this shop in Plaza (Karachi)
Its called Kashmir Autos,
I purchased Marshall nitrogen charged shocks and BDL springs from there and I must say,
the results are excellent,
Im really happy with my suspension,
I gained an extra 3 inches of lift which is what I was looking for,
also the suspension is much more comfortable than either of the experiments or the stock suspension,
the people there did an excellent job fitting it too,
I have had the suspension on for about 6-7 months now,
theres no noise during compression, I have been over some pretty bad bumps pretty damn fast, results are excellent, also there is lesser lurching during emergency maneuvers, it corners better, there is much lesser play during excessive and sudden braking, and there is never a peep from the suspension,
the shop was called Kashmir Autos,
its on Plaza, closer to the corner,
it has a large model of a yellow shock absorber on the footpath outside,
they also had springs for cars with CNG which bring them back to original height etc etc,
I would recommend that u stand there, get the springs / shocks watever fitted and then go for a drive around the block before paying the guy,
keep doing that till u r totally satisfied,
my rear springs were fine but the front springs wree not so I had him change them thrice before I was totally satisfied,
also make sure u have a good set of tires and keep them correctly inflated according to the manufacturers recommendations as they have a major role in dampening,
I went for Dunlop All Terrain II, obviously being a jeep, this tire will not be suitable for a car,
I would recommend this shop in Phase II DHA called Zafcom near Masjid Tooba,
they also have a shop in Gizri closer to the Punjab Chowrangi side,
make sure that u r at the correct shop as a friend of mine went to the wrong shop and the guy lied that it was zafcom and sold him tires,
the gizri shop is a long vertical signboard which says zafcom,
let me know if u need more information as I spent a lot of time looking the right suspension set up in Karachi,
I was at the verge of importing an Old Man Emu lift kit from USA which was costing a hell of a lot of money but fortunately found this dude,
he will also import the type of suspension u want, tell him the brand name model number etc etc etc and he offers to import most of them if they are stocked by his foreign counterpart.