Hello,
I'm trying to decide on an engine and have a few basic questions.

There is a .45 abc with 1.5hp at 16000rmp, 16000rpm max, and a .51 ringed with 1.5hp at 15,500rpm, 15,500 rpm max. What is the advantage of the larger engine here?

Are there any disadvantages to a remote mounted needle valve?

All the engines I'm looking at range from 1.5hp to 1.8hp(Tower's Brand?)...Is this enough of a difference to be considering?

I currently am flying a trainer but want an engine that will hold it's own in club dog fights, hopefully towing around Hangar 9 Sundowner 50 ARF, Phoenix Giles 202 46, or something similar (low wing sport, 5-7lbs). Thanks.