Im going to be honest with you. I have ran p5's vspec's and sirio's. With out a doubt the best engine I have ever ran is my current one, a rb concept s7 l2g. It was the easiest to break in and very, very easy to tune. I have almost a gallon on mine now and i raced yesterday all day with not one flame out, and the warmest it got was like 245. Another engine I might would try is the new grp.21. As far a servos get futaba or ace