Ok, fair enough, but the mods will probably move it on you anyway since it's engine related. I don't own either but have close race buddies that run both. The P5 has been around for a while with very little changes and is rock solid as far as durability and has a really great bottom end. It's a workhorse motor.

The Plus 4 is a newer and IMO more advanced engine with a linear powerband and better runtimes. I run a truggy so If I was choosing I would go with the P5 for price, bottom end, and durability. But, most of the racers I know prefer the smooth power and run time of the Plus 4.

That's all the better I can do on these. Like I said I don't own either but I see both run at least twice a week. I have ran them also in their buggies and have helped them tune them in, so I'm not just shooting off at the mouth here.