I believe that the sts .28 will outrun the os. 21. I have been in the break in process but the crank rope is totally gone now. As far as the temp its always hot and humid here, the day I checked the temp it was 75degrees with 100% humidity. Mabey I need to richen it up a little. I have been using info that I obtained on here to set the motor with and emailed info. Later next week I am going to run the savage sts against the tmaxx os21. Hopefully I will finish the break in process on monday or tuesday and be ready for the weekend. I am going to try new settings on my tranny for better whole shots. I will keep you guys posted to my break in and future race. I lookforward to eating a tmaxx... Just my opinions though..