he wants to jump from a stock S4 NA into a 350hp monster
my guess is he'd crash inside of a week if he doesn't upgrade the brakes, wheels & tires, and suspension along the way

I can't count how many times I've heard people bitch about getting worse handling after they've upped the power. Where they used to go full throttle in through a corner and now they are fighting understeer through the corner.

I have a good friend with an LS-1 swap FC FS: 1988 LS1 RX7, Central VA - RX7Club.com and he has a hell of a time keeping it under control in an auto-X. It got better with a set JIC coilovers and a set of FD wheels but it still wants to roast the tires off in 1st and 2nd gear.