when i ran a 15.8 i only had a header(4 into1 one piece) and crush bent piping(2 1/2inch), i was on the stock intake box. i also ran it with a 3/4 full tank and full interior. no spare of course. i also ran with falken ziex ze502s which everyone knows SUCK ass for any kind of driving. when i ran again(different day) my clutch was slipping and i had my timing back down to stock. i ran a 16.1
i also just realized that i had 2 leaks from the engine. i fixed one and the other is the slave cylinder on the tranny which doesnt hold pressure.

im installing my clutch this week, and im on better tires. the track just opened up a couple weeks ago. so when i have time ill head back, its a 200 mile round trip. this is all with over 155K on the clock.