I am in the middle of a total TM AK47 upgrade/rebuild. I looked at wood kits for a while and wound up saying "nyet"; I wound up buying a King Arms OD plastic furniture set for it (I can see the purists puking now).
I want my AK to look distinct. With the OD furniture, a G&P metal body/front set kit, a side rail mount and a Belarus made, real steel scope mount, it will
Besides, the OD has the practical benefit of helping to break up it's outline in the field.
I didn't get a wood kit for a few reasons.
First, the problems you are experiencing I found to be common (different color wood and fitting problems). Stock wobble was also a common complaint.
Reports I read seem to indicate wood kits are not very durable, having a high rate of cracking and splitting (how many AKs have you seen with the wood taped up?, yep). The finishes on some of them are said to be low quality, and discolor and stain easily. I play hard, and I want something I don't have to baby.
There are also problems with battery capacity. The unmodified G&P wood kit is supposed to take an 8.4v large battery. I had the opportunity to play with one of these kits at my local airsoft retailer and an 8.4v large was a project to get in the stock. Then you have to fit the 2 butt screw retention plates in the back of the stock and thread the 2 butt screws in them. I was in a well lit retail store, on a glass counter, and I had trouble putting the battery in. I can't imagine doing it in the field.
As for my King Arms OD set, I had to file off about 1/16 of an inch off the front of the top foregrip cover to make it fit; Not a problem, it and the other pieces fit really tight now. The plastic stock is caverness, and the butt plate screws directly into the stock into metal threaded inserts. The screws are longer then the stock screws, and are finer thread (they should not come on by themselves). An 8.4v large battery fits with plenty of extra room. I can also fit a 9.6v 3000mah nunchuck battery (from my son's G&P M4) in it. It looks like one of those 9.6v large AK batteries should also fit (though I haven't tried one yet).
I searched for weeks, and posted on several forums during my wood stock information quest, and didn't really get a lot of feedback about this subject. Hopefully this might help someone.
Red Alliance has the most information on wood kits and AKs in general:
http://www.red-alliance.net/forum.html
No question, a good wood kit on a good AK looks great, but IMHO, is not the most practical option for an airsoft AEG.