Heres a guide to let people know what mods do what to the engine performance

Start simple,intake and exhaust

Induction kit=Allows the engine to breathe air easier due to the lack of restriction,however,also allows hot engine bay air into the intake

Exhaust=Flow the gases more freely to get all the gas out of the chambers quicker

Throttle body change=Allows the engine to flow more air in as the throttle body is larger than the standard one,IE 2.0 zetec TB on a 1.8 zetec 52mm instead of 45mm

Next comes more extreme stuff

Chip:Remaps the engine management to control how much/when fuel is injected into the engine.Manufacturers make them for emissions/economy,Re-maps make them more powerful at the expense of economy

Cams:Control how long the intake and exhaust valves stay open thus dictating how much air/fuel goes in each time and how much time the exhaust gas has to evacuate

Gas flowed heads:Allow the air drawn in to flow a lot more freely so the engine can draw in lots more air per revolution and match it with more fuel=more power


Forced induction:Forces air into the engine by means of a compressor,more fuel added to match and more power thusly

Hi-compression engines:Using forged components to squeeze the air and fuel in the pistons to extreme levels,thus creating very powerful explosions

Budget and what to do

Normally aspirated cars (non-turbo/supercharged)
Less than 500 pound=Exhaust system,induction kit..........chip if your lucky
Less than 1000 pound
As above with the addition of camsand live mappable chip instead of fixed chip
Less than 2k=As above but with better cam and major free flowing head and exhaust manifold
More than 2k=Independant thottle bodies and management.Negates the need for induction kits and can give mega power on their own,combined with the above(head work and exhaust) mega power can be seen

Budget and mods for turbo cars
Less than 500 pound=Exhaust system to remove lots of back pressure helping boost,induction kit to help turbo suck air,Boost controller
Less than 1k=As above but with uprated turbo actuator and chip,exhaust manifold possible
Less than 2k=As above but with uprated turbo
More than 2k=Front mount intercooler,Uprated internals to handle mega boost,Over 15PSi boost possible

Guide written fully by me and will vary from car to car,prices are rough guides