these 3 things will help the most, power isnt important.
vehicle suspension setup - keeping the vehicle balanced through the corners and into braking is where you will save time.
brakes - good brake fluid for when you decide you want to brake more aggressively & deeper -- MORE USEFUL MORE MULTIPLE LAPS RATHER THAN 1 HOT LAP
tyres - grippier the better -- BUT the more track orientated it is, the less likely it will go "squirmy" on you deep under brakes after 2-3 laps, I've had Toyo T1R's essentially melt on me after 2 hot laps, but funnily enough had a control tyre (Nexen N6000 235/40/R18) last a half decent distance despite being a cheap daily tyre.
if you want to play, you have to pay.
get a good street tyre, and a set of circuit orientated tyres for the track.
by circuit tyres I mean semi slicks, and I dont mean those POS westlake tyres etc
you want Bridgestone RE55, Toyo R888, Pirelli P-zero Corsa, etc