If you go to tower hobbies the Picco is about $175, and they currently have a deal to get $10 off. I've been extremely impressed with its power and the ease of breakin and everything.

Remember, if you decide to go with another engine you can send the Mach back (and don't need to worry about how long it takes) then when they return it just drop it on eBay.

The LST is really a great truck when you actually get to run it.