Are you planning on getting the stage 1 for that price? If so I heard the ride is OK but might not be much better with the current setup you've got. My buddy has the stage II with the MX6 shocks and the ride is better than stock IMO.
Personally, if your going to go with the six inch I'd save my money, sell what you've got when the time comes get it right the first time and avoid spacer's all together. As far as 35's think twice, after sometime you'll probably end up wanting to re-gear and if you've got a 4x4 you have to do both cases which can be a lot of $$$! Plus you'll still have rubbing issues like most people do with a 3" lift and 285/70/17's. 33x12.50 M/T's looks pretty sweet with a 6" (that's what I'm currently saving up for!). Good luck.