You will have to see what the class rules are for SC and Oval in your local area. I believe most oval racing is not 2-cell, but may be wrong.
The gear you mentioned can't do single cell lipo, or 4-cell NiMh. The GTB goes fine, but is not really a race spec.
I use Tekin, and their esc's are second to none. The RS and RS Pro can do brushed, brushless, 1 cell or 2 cell lipo, any NiMh from 4 cell up, and the Hotwire interface is easy to follow.
Many racers still use older and lower spec gear, and have fun doing it. THe only problem is, when you need a specific application (like single cell lipo), you need to go out and get new gear.
If you are budet concious, look around for some top-line 2nd hand gear. If you aren't budget conscious, just get the top stuff straight off.
THere is always a bit of $$ paid for marketing by the big companies, but if they were no better than the cheap stuff, don't fool yourself into thinking you will be the first person to find out, because many have looked into it before