both motors have the exact same block, the f54 was on both, the turbo motor has a better head, the p90, it flows better because of the exhaust ports but everything else is the same (other then the pistons and cam). the na would make more power on stock boost but with the p90 and dished pistons the boost can go up higher, safer, making more power. the boosted NA would be more responcive off boost, but on boost, do to the higher commpression it is more prone to detonate