I have an LRP X-12 9.5 motor stored, but was just too lazy to put it in my RC10, then after the 1st qualifiying round was over and I was TQ, I decided to just leave it in as I didn't feel the need for more power to go faster. I'm not a big fan of wheel spin (increased tire wear) or wheelies when the track blue-grooves and like having just enough power.
On one weekend race event, I ran the 2WD Stock and 2WD mod classes with the same car, same motor (13.5) and same battery back to back. It is hilarious when people realize you are running a stock class motor in the modified class and are doing the same or faster laptimes than the top 3 or 4 racers in the mod class with a 20 yr old style buggy and to boot, 1990 style wheels and tires (not the new wheels or tire compounds)!

On this day in the pics, I ran Associated Team Car front wheels with Proline Edge tires, and in the rear Team Car wheels and Losi X-2000 tires I have had glued to rims after trying them way back in 1994-95.
By the way: Good Luck Derby Dan and others racing the vintage cars with the current cars. It can be done and be a huge amount of fun!
I prefer my RC10 buggy over it's grandson, the RC10 B4.