My first track event, the instructor had the fastest lap time in the rental Thunderbird he picked up at the airport. Faster than the Vettes, Z's, Beemers, he beat what everyone brung, just with driving skill
And prob the mod that would make give you the biggest improvement in lap time is better brakes. Stock brakes suck and overheat and fade quickly on the track. You need to be able to carry your speed further into the corner.