I've seen a lot of posts on the R2 being the pick to go with the IA, but I'm thinking the R5 might be better. Being able to flip over a crit is pretty good, and it's really the Y-Wing that's lacking in the Green department, anyway.
Although, you might never use that R5 since the X only has 2 hull, whereas the Y has much more hull. Perhaps the R2 belongs on the X-Wing, and the R5 in the Y-Wing, making a tough ship even tougher.