Engine mods

If you are keeping the same displacement, then you can't really increase torque without forced induction (turbo/supercharging). O.k. you could install nitrous, but that's an extreme option.

When most people 'tune' thier engines, they allow the engine to rev more freely - this gives more power, but no extra torque, unless the original intake/exhaust was very restricitive (which it isn't on the 306).

Alternatively, you can make the car lighter, by stripping out non-essential items. By removing the spare seats/wheel/running a half full petrol tank, you can pretty easily loose 10% of the car's weight, thus increasing the power-to-weight ratio. Done carefully, it's completely reversible, so the car is still saleable, it's free and it doesn't put any extra strain on the drivetrain, so reliability should be unaffected.

If that doesn't appeal, then from a purely pragmatic point of view, it will almost certainly be cheaper and easier to sell your existing car and buy a quicker one - insurance on modified cars is usually expensive and the resale price will probably drop, so you get no return on your investment, whereas if you spend the same buying a faster car then it will be worth more at resale.

All the best, Andy

So I could add a forced air induction kit and lose some weight in the car.. The spare wheel can be removed but not the back seats as I need them.

I havent brought 17"alloys etc because of weight but have bought a suspension kit to improve handling (40mm drop)..

My engine is tappety recently and there is a clinky noise from the exhaust which I think is amy cat converter going/gone

If I have my cat replaced and my tappets realigned should I expect some gains.. I dont want to remove the cat because of MOT etc..

Ive got a powerflow exhaust on And its going to be lowered with the weight reduction The Induction kit can be fitted soon.. Should I buy one of them chips for the engine to improve erformance and to go a bit bwetter on handling maybe a strut bar?

non-essential

It's not my place to argue, but are you sure that's a good idea? On many mainstream models dropping the ride height tends to improve handling at the expense of ride comfort, but the stock handling of the 306 is very well sorted to start with, and it is quite possible (even likely) that altering the suspension geometry (e.g. by lowering) will make the ride AND the handling worse.

Um. By 'forced induction' I meant turbocharging or supercharging, not an 'induction kit' of the K&N / pipercross cone-filter variety (which make a nice noise, but don't improve performance). Installing a turbo is possible, but it requires significant engine mods, and isn't cheap.

Performance chips for non-turbocharged cars don't really do anything, and aren't worth the several hundred pounds they cost.

If you want to tune a 306, I'd recommend you get a 306 TurboDiesel - they are MUCH more tuneable that the petrol variants. They have 150lbFt of torque as stock (compared to 119 for your car), and can pretty easily be tuned to give 200+ lbFt.