I had one limb crack on my 08 Firecat close to 2 years ago now. Martin replaced both limbs with new 2009 limbs and to this time they've been holding up well - no issues with the bow in any regard since then. As best I know the 2010 limbs, cams and Roto-cup weren't available at the time. I don't know if Martin would have opted to replaced everything like Barry's Firecat at the time he had his repaired, but at this time I'd say it doesn't really matter since it's holding together and shooting well with what it has.
As for upgrading, I'm awaiting the arrival of a recently ordered TRG/SOS system and the new VEM riser dampeners. One poster, dan476 I believe, installed the TRG/SOS on his 08 Moab and reported success in doing so. The difference between his Moab and my Firecat is in the cams - Moab has M-Pro single cam and Firecat has hybrid CAT cams. So, based on his experience and a few others I've read do this I decided to try it on my bow. I had hoped to get it by bow but it's still apparently "in the mail". I'll be reporting my findings here and AT after I've had some time to work with the TRG/SOS.
Anyway, congrats on your choice of bows. I'm betting you have a fine shooter.
2008 Martin Firecat Pro-X (29" DL, 66# DW), home-made TRG, new VEMs, DS Advantage/HHA Pro-5519 front sight, No-Peep Sight Eliminator, Limb-Driver arrow rest, B-Stinger stabilizer/dampener, custom upper STS, G5 Head-Loc quiver on custom mounting bracket. Gold Tip Velocity XT300 arrows with Bi-Delta 2.5" Sharkstooth vanes and Grizzly single-bevel broadheads, 498 grains at 262 fps (22% FOC)