Ok, I put the +2 on my 15 rounders:
1. they do go easy on/easy off
2. they are the correct fit
3. I am using 9mm - so yes it adds 2 additional rounds for a total capacity of 17 rds.
*one side note... when you first put on the +2 baseplate the internal baseplate usually seems to get a little hung up in the mag so you need to take the end of a writing pin or something long and norrow and reach in the small hole in the baseplate and push against the internal baseplate (to unsnag it) to make sure it drops down all the way and becomes flush so you can put in both extra rounds.
So in sum, it was a success! You can put the +2's on the 15rd mags as a well as the subby 10rd mags. Good Luck! Hope this helps!
