I also "upgraded" to the 72x for $30 after my 52x died late last year. If your current drive stopped all you gotta do is email tech support and they will give you an RAM number. After I got my RAM number I called customer service and asked if I could do the "upgrade." However, it did take calling them a couple of times to get through customer service. I called during the day.
I upgraded to the 221 firmware once I got it and haven't had any problems, although I haven't tried CDR or CDRW disks. I rip UP TO 45x, actually up to 50x peak. It basically does ~28-30x min, upper 30-lower 40s average.