Don't forget about the nitro Rustler. It has a completely metal chassis and comes with the 2.5r. The 2.5r is a little peppier than the pro .15. The Rustler is supposed to be a bit more advanced, but the nitro sport comes with adjustable turnbuckles. Where the Rustler doesn't. Strange... Never the less, they are both very simple rigs and hop ups are plentiful and cheap.