Which 1800 engine?
I think your best bet for a car of this ilk (am assuming it is a daily driver), is to find out who makes the best tyres/pads for your car. Unless you want to spend a lot more money on it (not recommended if you want to sell it on again), you'll just kill its resale value.
Anyway you may wish to check
this link for tuning your motor.
(P.S. Why did you choose this car?)