Got to agree regarding the hop ups. Early on I tried every hop up on the market. Some actually make the car perform worse. The K tank stops some of the foaming issues when running a hi output engine. The update AE tanks are fine too (update was about 2 years ago) If you have the RTR plus it will have the updated tank. The difference is the old tanks held around 77cc of fuel with out the insert & about 72cc with the insert & the pressure line ran from the top of the tank. The new tanks average 74cc capacity without the insert & the pressure fitting is in the lid. The capacity is only an issue at sanctioned events, but the pressure fitting move solves a lot of engine reliability issues. The carbon side brace can save the pipe being driven through the tank after a side impact & is well woth the investment. The only other hopups I would bother with is the alloy input shaft cups, just make sure you use the standard front shaft as the alloy shaft is crap. Other than that the car in Factory Team spec is fine. I am not sure what the RTR plus needs to get it up to FT specs other than carbon bits. I wouldnt worry too much about the blue engine mounts etc. Threaded shock bodies would be the other upgrade if it doesnt already have them.
I have also tried the BMI chassis V1 & 2 they have their advantages, but when I got Kyles setups they were based on the stock chassis so I went back to that. Since then I have stayed with the stock & all my setups are based with that too. If you want to try one I can hook you up for a lot less than $170.00 US. Another neat trick (thanks again Kyle
) is to block off the standard pressure hole in the pipe & move it further forward, it also helps with the fuel foaming. That one is more relevant when you ditch the pullstart in favour of a bump start engine. Also the K tank wont fit with a pullstart.