Bypass the Fast 12 and go with the XTD 14.5. Its a beast. I deal with Adams tour equipment and can't keep the XTD 14.5 and the tour only XTD 3T heads in stock. Very good 3 woods.
$600 per wheel is high. The installation is pretty straight forward and nothing too complicated. Front wheels can be a ***** if you don't have a lift. Seems the $600 per shock quote is pretty standard for Chevy dealers. I have a Z71 and was quoted $600 per shock too for Bilstein. Bought them...
Both, Cherokee and Plantation, are very easy and not very long. Fairways are usually in good shape and so are the greens. The ball sits up nicely on the zoysia fairways. The courses in Tunica are better but that may be a little farther than you want to drive.
Like other person said, its hard to go wrong with any major brand these days. Assuming you got the correct flex in shafts you should be good to go. If you ever wanted to get them dialed in I'm sure there is a club guy near you with a launch monitor to help you with this. This can get pricey...
Make quality stuff now. Find a few that fit your eye, get on a launch monitor and try several shafts until you find one that gives you the best numbers. The newer stuff will launch higher and spin less than what you have now so you should pick up some distance.
It could be oil residue build up or low oil level. Also, the selectorlinkage might be out of adjustment. I'd have the oil changed and see if that helps first