I had the same problem with my 99k. A cogged belt fit but I just don't like how they look. I finally got the round stretch belt. If you got the 15"-21" one it won't put a strain on the motor. If you were at the higher end if that spectrum (say you needed a 19" belt), I wouldn't recommend it though.
I luckily, was also at the lower end & the stretch belt works fine AND looks much nicer than the cogged one. It fit nicely without stretching & I have room for adjustment.