The system you want is the Novak 5800. They make a good system but there are two variations. The 5800 and the 4300. The 4300 more closely replicates a stock 27turn motor in the stock setting (there are 6 settings on the ESC). The 5800 is quicker in Mod mode (double check this). So if you are racing, and the track will allow brushless to run in stock versus other brushed stock, that would be your deciding factor (some tracks let you run brushless in Novice and intermediate, check with their rules). Also, some tracks do a brushless/ stock race. Weigh your needs and what you plan on doing, then decide. The brushless is very low maintenance, and if you race mod, or want the best performance in a brushless motor, the 5800 is your choice. I ran the 4300 in my b4 and it was great, but I ran in to limitations as I improved. It is actually more torquee and quicker than a true stock motor, so as I moved up in classes, I wasn't able to race it in normal stock anymore. Plus, in mod mode, it just can't keep up with good brushed motors. I found it was about equal to a 14 turn. Now I have to run it in brushless class only, which isn't very common. It is more common in touring cars though.
The esc that comes with either motor works with both, so you can purchase the system with either then pick up the other motor later if you want more versatility.
RC Car Action Editor and Photographer