For $50 you can't go wrong. I have one of the Magnum XLS 46's in the Model Tech Mach Racer that I reviewed for RCU. That engine screams like a stuck pig. It's really a great combination for that plane. From what I have seen on Magnum is that you either get a great engine, or a dud. There's not much else in between. But if you do get a dud they are very good at customer service and will hook you up. WIth the recent sales going on a few of my flying buddies have purchased Magnums (both the 46 here and the recent 52 4-stroke that they sold) and they have been really happy with them so far.
But for the money on this sale it's really worth it.
Oh yeah, by the way, I ordered 3 of them from the sale if that helps you out any!!!
Ken