Hey bballer. Sorry for assuming you were new to the hobby. Sounds like you know what's going on if you race carpet. It's a LOT of fun. I finally got to race carpet again in Dallas last weekend for the first race of a new track that opened.
The MT12 is faster than the OS. I've heard the same that the OS is down on power. The MT12 is pretty easy to tune too, like other Novarossi based designs, and it's in your price range. If you want a faster engine, the MR12 is a good choice, but they are hard to find since they are primarily a MTX3 kit engine. Other than that I've been really impressed with my NS12S3, but they are pretty expensive.
I'm using a Futaba 3PK now. I have a PCM receiver in my MTX3 and a HRS receiver in my Xray. The HRS is a PCM receiver with faster reaction time, but is for digital servos only so I don't use one in my nitro car. I can't remember ever having a glitch in either car with those receivers. The cool thing about PCM is, the receiver 'locks' onto your transmitter's signal and is better at filtering noise from signals that aren't from your transmitter. The futaba is a pretty strong transmitter too. I've actually made a guy with a KO Mars move down to the other end of the drivers stand to keep my radio from glitching his car! It's only happened with that one guy though.