I'd stick to a 46 class engine, the plane will fly better if not weighed down too much.

I've also had some issues with the EVO PTS 46, on a fellow club member's mustang. Found that the idle needle is VERY sensitive, and that it turns too easily. Only took about 5 degrees to go from too rich to too lean in the idle. Very difficult to find the sweet spot for clean transition. High speed needle was pretty normal, iirc. Limiters had been removed. When we did get the mixtures correct, and in this engine the idle mixture is absolutely key, it did run pretty well, putting out mid to high 11k rpm's on 11x6. Whatever you do, don't use the 3blade prop that comes with it, not enough grunt for lively accelleration and climb rates.

I run an AX46 (OS), and it's an awesome engine. Very easy to tune, very reliable. Mine hasn't deadsticked in it's 50+ flight life, even though it's lost the muffler 2x (broken thru-bolt due to my over tightening.... ) Now that it's well broken in, it's turning 11x6 MAS at 13,300 rpm riched for flight. It's on a 5.1 pound Dynaflyte Fun Scale Mustang 40, and gives it unlimited vertical and the most impressive high-low pass speed. Should hear it winding out in a dive. Beautiful.

I broke in a SuperTiger G45 (which is a .46, go figger) for a friend this fall. Hasn't flown yet, but my initial impressions were favorable. It started easily (2 turns out, not 3 or 4 like in the manual, too rich to fire), and had no trouble exceeding 13K running rich on it's first start with the same 11x6. This engine was VERY tight new (literally squeaked thru TDC until run in), so it's gonna gain RPM with breakin, and I fully expect that it'll end up stronger than the OS. It's going on a CG Eagle II trainer. Some people find Supertigres to be a handful to tune, but I've not experienced any difficulty with the 2 I've worked with.

Well, that's where I'd start. The ST goes for somewhere around 65 bucks and the OS in the low 100 range. The OS is friendlier to tune.

Good luck,

J