Satoch, the engines come with 1) .1mm shim and 1) .2mm shim

Dotan in buggy my personal favorite is the 7port, the engines are very similar since they have the same intake porting. Its hard to say which one is more powerful the 7port spins more rpms while the 5port has more torque. The difference in powerband is very noticable, the 7port is also more sensitive to pipe clutch combo then the 5port. I think it comes down to what you like on the track.