I am currently riding a 2009 Rockhopper, and lately have been debating upgrading the stock Dart3 to a Reba air fork. Whilst browsing classifieds I came across a 2008 Stumpjumper FSR frame and fork, that comes in at my budget. I have a couple questions though.

1) Is it a worthwhile upgrade? I would be swapping parts from the Rockhopper onto the Stumpjumper, and then upgrading parts as they break, my frame is an M4, the Stumpy is an M5.

2) How problematic is the brain on the Stumpjumpers? Can it be upgraded/swapped out?

3) I know there were some fairly big changes to the Stumpjumper in 2010, but how large of an improvement are they over the earlier models?

4) My current frame is a 19", and often feels small. The Stumpy is an XXL. I tried to compare geometry, but since its HT to FS it is kind of hard to do so. I am 6'2" and definitely would not want to get something that will clearly be way too big for me.

5) Assuming I go through with it, what would be a reasonable price for my Rockhopper frame? It's a 26" frame, and would include fork, cranks, BB, headset, LX front derailleur and seat post. I figure somewhere around $100-$150?

Thanks.