I've had the Patty with the Moki 2.10, the BME 50 and the DA 50. I sold another ARF that I had in my garage to a friend of mine that had a 1.80 laying around. I told him I didn't think it would do the job, but... Low and behold, it does pretty darn good. He flies the advanced AMA pattern and it does everything that the pattern consists of and more. Torque rolls with demanding pull out power, no. But for everyday sport flying, and especially for the Advanced Pattern, it does darn good. Since the mount would be the same for the 1.8 and the 2.10, I would suggest you go ahead and put the 1.8 in her if you've got one laying around. If it doesn't work out to your likings, you could always change it out for the 2.1. By the way, another thing I wouldn't have done that he's got is an 18X8 Master Airscrew Classic prop. I always used the Menz, NX or Mejzlik. I need to look into this inexpensive Master Airscrew thing. But if you're starting from scratch, then go the 2.10 from the beginning.