I've got the Tower .40 which is no longer made. It does pretty good. The Tower .46 was noted for having a leaky crankshaft bearing and a lot of people complained about it. I would recommend going with OS engines. They are a few more dollars but well worth the cost. I have 3 OS 46 FX's and 1 OS 50 FX. The OS 46 FX's have many flights on them and I have never had a problem.

Just my 2 cents.