300+whp build advice

Keep in mind even the intercooler can fail your visual inspection, so it really will depend on stealth and someone to look the other way…

Amen…!!!! Armeboot

Leak down test? Are you referring to a compression test. If so, compression can fully be at specifications. But the miles of the engine can tell us the mechanical integrity. If you can boost a "z31" at 14psi say, and the engine has 300,000 miles and something doesn't go wrong, you have a godly engine. Funny thing is no one has godly motors. Engine integrity is always a first when rebuilding and it seems you have a good goal. I mean, you can go ahead and and slap on some extra screws to make it faster.

Compression tests don't tell you how bad the rings and valve seals are, you can have good instantaneous compression but still leak a ton… hence the leakdown test

My 0-60 is under 5 seconds with a MBC T3 10psi no intercooler, No AC, full CM 3 inch turboback, ASCO gutted plenum with a cover (looks 100% stock to any cops or emissions), and 300lbs of weight reduction. i'm in Cali and my bay looks bone stock. It pulls on E46 M3s, 350Zs, G37s, WRXs, and other "decent" stock cars. This setup would work well for your speed goals and it has a great powerband and response thanks to the plenum.

This. Leakdown is a much better indicator of overall engine health. Compression is a decent quick test if you don't have access to leakdown gear, or are trying to do it on site before buying.