help needed with 904

Well I went down to get the parts and of course they had the tail gasket which should have been in the kit. nothing in a shim kit. Of course they gave me the same shim that I already had which had an extra two hundred thousand on it. Another transmission warehouse even an older one in town and they had a big huge shim kit they wanted another $30 for and I'm not going to spend more money on this transmission like that if I don't need to. I need to do a little research here to see if how much this is going to hurt performance and or longevity. If I come to find out that it's not going to hurt performance and it may just hurts a little bit of longevity then I'm good to go. The second transmission warehouse actually had a part of the shop that did transmission rebuild and their mechanic came out and said that if I'm going to run a shift kit and drag racing and stuff like that that I would want it on the loose side anyway. So we can leave that one out for arguing if you like.