if you wanted to keep it N/A
youd go A full custom intake and manifold, full exhaust, headers all the way back, with high flow cat, a single muffler, 2.5" pipe all the way through
Thats about the extent of bolt ons.
Then you get into things like cams, valve springs, over sized valves, port/polish the heads, port match the heads to the intake and exhaust manifolds.
Then an aftermarket ecu, get it tuned, lift the rev limit.
Then the bottom end, rods and pistons.

