Forest River took care of an axle issue on my friend's 2004 Rockwood. The axles were not manufactured by FR!
As for mirrors, you might find that Titan mirrors will fit your Nissan. I have an Xterra, and parked next to my friend's Titan. We eyeballed the mirrors and the shape of the mount. They appear to be identical. I decided not to go that route due to the square Titan mirrors may not look good on my vehicle.
I got a free set of clamp on mirrors from the same friend. He didn't need them after buying the Titan with the towing package, which included the extendable mirrors I was admiring. The clamp-on ones work fine, but aren't exactly asthetically pleasing. Oh well, the price was right.
Robert & Dawn
2007 Rockwood 2502
2010 F-150 FX4
Equalizer Hitch -w- 1000# bars
Yamaha EF2400iS generator