www.monstermiata.com

it will give you everything you need.

on nitrous i put out 250rwhp and without nitrous i was running 180rwhp. and trust me it felt plenty on the juice. i had a 2002 and it was built. i couldn't imagine more than 400hp in a miata, the driveability would be shit IMO. honestly if you need that much power swap in a SR. you can build a SR as cheap as a honda these days. ZRFEVER has one. check them out