He's full of shit, race him and laugh... How careless would you have to be to not know what parts you put into your car? And doing a piston swap isn't exactly cheap, he doesn't know what size injectors he ORDERED and INSTALLED? This guy is a total tool, and you will certainly win.
Also, nitrous is usually only injected under WOT conditions, and I doubt he's riding around for 15-20min at wide open throttle rofl. What an idiot.
He doesn't have high comp pistons
He doesn't have nitrous
He doesn't have injectors
He hasn't beaten an M3
He can't go 200mph
If he can get to 60 in first gear, thats good news for you, because his first gear is tall as fuck and he'll be bogging like shit off the line. That being said.....
He can't reach 60 in first gear
You can beat him
You will beat him
You SHOULD race him
You SHOULD laugh