What motors / battery did you use? What was the battery life, and how fast could it go? Any tips / regrets? Sorry for the bombardment, but I'm looking to do something similar.

I recall reading this question, but apparently forgot to answer years ago.  I used the stock motor; if my research at the time was correct, this model car was already 20 years old. It had a compartment for 7.4V NiMH batteries, which I bought off ebay or similar at the time.  I think I could get around 15 minutes of run time before the speed went down a bit? Maybe a bit less.  Speedwise, pleasantly fast!  One time, the bluetooth connection stopped (computer went to sleep when I closed the lid, and was attempting to drive with a usb keyboard? unsure), and I had to run to try to catch it... it found a wall before I could get to it, but was ultimately fine.

Zero regrets. I'm familiar with better electronics these days (and better stuff is available, too), so would do it in some manner differently if I were doing it today.