what can i do to improve performance
Unfortunately, there's not too much you can do with these engines, without considering spending a bit of $$$ in the process... such as upgrading engine internals (lighter, stronger pistons,like wiseco products for instance) pushrods and all that other good stuff... if you're keeping it on the less-expensive side, make sure you upgrade your conventional engine oil to full synthetic, along w/ a good quality filter, upgrading the stock air breather box to a pop-charger(allows your engine to snort that clean air a whole lot better. And PLEASE use the platinum spark plugs as requested-iridiums... makes all the difference. Oh, these plugs love the premium fuel too. Don't sell yourself (and your car) short on that low octane crap either. Don't be "fooled" by the so-called horsepower boosting, plug n play chip either!!! All they're good for boosting is bullsh#t!!! No computer upgrade=no extra power!!! GOOD LUCK!!!