6-8 psi means nothing. You need to have a hp goal. What B18 are you boostin B18a, B18b, B18c1 or B18c5? What condition is the motor in and how many miles are on it? You will need to use 91 grade fuel or higher under any boost and have a tune! A stock B series should be fine for 200whp if the motor is in good shape. Any more than 200whp then you will want to build the bottom end.