Guitar, that engine is the one that nearly sank Evolution before the company really even got started well. I had one, and it wouldn't run reliably no matter what I did to it. I know how to set up and tune engines, but that one was so unpredictable. There's a good reason it's only up to $30.
Seriously, get a Thunder Tiger or (better) an OS. The few extra dollars you'll spend will be more than made up for in the saved aggravation of an unreliable engine. The big benefit to the beginner to go ahead and get something good is twofold- first, if you have a problem, you'll have a reputable company to send it to for repair. Evolution has a good reputation for service too from what I hear, but that's only going to apply to their current models. That discontinued one in the Ebay ad won't get fixed for free. Second, you'll likely have an engine that runs right out of the box, which lets you learn the nuances of how an engine is supposed to run. There's nothing worse than trying to learn how to tune an engine and having it quit on your randomly. You'll never know if it's something you did or just a junky engine.

As for being overpowered, that's a good thing for a trainer. Newbie pilots often get cockeyed on the runway and will want to jerk it off the pavement as quickly as possible. Being a touch overpowered lets you do that. It also lets you cut through the wind better and power out of stalls when they happen. I truly appreciate the beauty and challenge of cruising around in a Cub at 2/5 throttle, just barely powering the plane enough to keep it in the sky, but that's not for a new pilot's first month of flying.