if you are going boost run it stock bore. i wouldnt even go 84mm. the little bit of extra tq gained is not worth the risk with the thinner walls. i have made 559@22psi on stock bore and stroke type r and also well into 600's at 29psi. i wouldnt buy a stroker kit unless going all motor and i still wouldnt buy the kits out there. i would get a golden eagle deck plate and order custom stroke rods and make your own kit. that would get you to a 2.1+L.