The p5 is the classic buggy engine. It has more torque than the plus-4, I don't know about the team version plus-4 though. the plus-4 has a bit more rpm and a better front bearing, and a bit more runtime....but my favorite engine is the p5. I may be a little bit biased, but for 240 bucks (Stock). It's a great deal.

I recommend getting a Houston tuned p5 with a silicone filled crank and the double sealed Novarossi front bearing, and a novarossi rear ceramic bearing. It's really nice and easy to tune, and will clear any technical jump on the track...

A lot of guys seem to like the plus-4 it is a bit smoother on the power and tops out with a few more rpms...I just can't retire my favorite engine line....