You're a good friend. I did the same thing when I started racing. I let a friend run my T4 for a several weekends while I was stuck with an old wore out XX-T that had very brittle plastics. It was old. But I really learned how to drive careful so I didn't break it from crashing. Just from landing. But it was fun, and now he's into the hobby big time.
--Driver...you are cleared into the track.....Smoke On.
--"U Ain't Fast!!"