I have a couple of upgrade plans on the go this weekend. The first was putting some C29ssmax (Mavic Crossmax 29ers) on the Kona Unit 29er. Crossmaxes make any bike look 10x better and this was no exception. What I wasn't expecting was the 550grams of weight saving across the pair of wheels. I'll let you know how the ride over the next few weeks, I think I will be very happy with the new wheels.
The second upgrade involves my race bikes. I have got hold of some Enduro bearings from DIYMTB and they are going to help me make my bike more efficient to ride. Firstly the standard BB was replaced with a Ceramic BB, now you can turn the pedals with a feather. I would also expect the ceramic BB to last longer when the rain come because there should be significantly less corrosion due to the non metallic surface. I also replaced the lower jockey wheels withe ceramic ones to reduce friction a little further.