Walaikum-us-Salam,
- Is its a good value for money
Dont know at what price you are getting it at so cannot say, however it was one of the best cars ever produced by Pak Suzuki.
- Spare parts
SGP genuine spares are hard to find these days, however spare parts of other companies, which are available in different qualities are easily available.
- Engine vs Body ratio
If you are talking about power to weight ratio then its perfect.
The car is not underpowered.
- Performance
It gives around 12 km/litre in city driving and around 16km/litre on long routes.
If engine is in perfect nick then it does 0-100km in around 15~16 seconds and is capable of achieving speeds of upto 160km/h.
- Modifications n expenses..
You cannot do much modifications on the stock engine to improve the performance drastically, however you can swap any bigger engine such as g13b, g15a or g16b to improve the performance.