You'll get personal preferences both ways on this.
I would stay with the stock 24's, make sure your fuel pressure holds up on WOT pulls.
24's will easily support 350 rwhp; there are 30's supporting 500 rwhp.
Is it tuned? What was the AFR? what was duty cycle? rwhp?
If the car will be under extended WOT, like roadracing, and if you're well over the 350 rwhp level, then I'd consider 30's.