Engine mods, What to do? Options

[Godders]

I am very new to the whole world of moding cars and am unsure what to do to increase power. I have a 1994 jap import celica gt. It's has a hks mushroom kit, straight through exhaust system, upgraded ht leads and upgraded sparkplugs. What else can I do to get the most performance out of my little beauty as it's quick, but it could be quicker. All suggestions welcome.

Thanks in advance

[bsamps4]

This may be a personal opinion, but I believe that it was lagos that posted a link to a test between different air filter types. Based on the results I would recommend swapping that intake for an AEM dry-flow filter intake. You mentioned that the car had a straight through exhaust system, but does it have an aftermarket header? What size is the exhaust piping? Have you replaced distributor cap or rotor? Typically the key to success with this type of thing is to always have the car properly maintained. Aside from that you would likely need to consider the use of a turbocharger to increase power, or perhaps a motor swap. Hope this helps.