personally id go boost,just cause im a boost person...on the other hand depending on the b series could be fun...but i cant figure out why you think it wont keep up with your gsr if it isnt built,youll be surprised how strong a boosted single with a good tune and good parts will move even stock ive seen a z6 on 12psi take a beating for 2 1/2 years completely stock but had a great tune...go boost