I'd just get the NT. I've got the TPS, or what used to be the TPS. When I took mine to the field for the guys to check out the first thing they did was take the baffle out of the muffler to gain another 10% or so in power. Then I ate up the TPS plastic spinner with a starter. Got an aluminum one that takes 2 blade props to replace it. You get a lot more power with a 2 blade prop. I also bought the thing that replaces the TPS flywheel, but haven't used it. The flywheel gives a newbie like me slower speed transitions, and helps it idle better at a low speeds.

The advantages of the TPS are slower idle, smaller 3 blade prop so you don't mow as much grass and have a bit less power.

Disadvantages of the TPS are less power (the NT actually has a slightly bigger displacement), A funny non standard prop that costs more, and a plastic spinner that you have to be very careful of when using a starter.

It cost me about $30 to convert my TPS into a wannabe NT. - Joe