306 1.8 xs tuning ??

[C.A.R.]

Don't de-cat the car if it's used on the roads - you lose a noticeable amount of torque as the engine relies on the backpressure from the catalytic converter.

GTi6 exhaust manifold, cat/downpipe and a new exhaust will make the car sound a bit fruity and might make a tiny difference to the performance. The standard management will be OK with this. Adding the GTi6 Manifold will however upset the standard management - warning lights and overfuelling will follow. It increases the throttle response - but then it would, the throttle body itself is nearly 50% greater diameter.

Don't bother with the inlet and only do the exhaust if you can get cheap parts and do it yourself at home would be my advice. If you still crave more performance, get a different car or strip the interior out!