if you dont wish to spend a lot but you want a little more performance do this.
warm the car up,
remove the spark plugs and pour about a mouthful of REDEX into each plug hole.
Remove your air filter, clean out your airbox with a lightly petrol soaked rag.
fit a new clean air filter.
Wait for about 45 minutes and re-fit some new, correctly gapped spark plugs.
start the car up, it wont start immediately but it will start.
when it does start it will smoke profusely from the exhaust.
Dont be alarmed by this, its just years of carbon crap thats been dissolved by the redex leaving the engine. Take the car down a quiet road and cane it a bit.
The first time i did this I thopught the car was smioking so bad that something bad must have happened, not the casae.
After about a mile or so you will notice the amount of smoke is less, continue razzing it about until there is no excess smoke from the exhaust.
take the car home. You will notice on the way that the car feels quicker in every gear.
once you get home reove the plugs again, another squirt of redex into each plug hole. leave for another 45 mins. re-insert plugs, then pour the remainder of the redex into the fuel tank. take the car out for a blast as before. hey presto its quicker and faster than it was the day before.
put redex in your fuel everytime you fill up (using the instructions on the bottle now) your car will run sweet as a nut