i would suggest that you have to deal with your Engine first before touching anything else. when the Engine performs on its maximum performance, that's the time that you can start improving its outward look and other modifications.
Here are things that you need to modify to Maximize Engine Performance:
1. Ignition System- spark plugs (ZERO resistance), HTW (Zero resistance), Alternator, Coil, Battery, Ignition Enhancer - (Enhanced Ignition could burn almost 100% of fuel inside the combustion chamber)
2. Engine Oil- Look for GTO (it is an "Almost Zero Friction Engine Oil" that could protect the oil rings, cylinder walls and etc., Lowers engine temperature and gives more engine power)
3. AirFilter- Use the one that has Vortex Effect
4. Exhaust- Use the one that has Vortex Effect too.
5. Others....(maybe, some istoryans can add more here)
the gadgets for modification I mentioned above could be found at DAJ Autoshop only. They specialize "Maximum Engine Performance"
dont worry about the price kay barato rana sila diha...