just realized my post didnt come out the way I wanted it too.
scer, Italeri has some tigers, panthers, jagpanthers etc. They are about 20 bucks. Thats what I got my Tiger for. I cant comment on the fit cause I havent built it yet. They will all come with the link-and-length tracks.
Try out Greatmodels site and see what the RETAIL price is. Not their price.
www.greatmodels.com
By doing this you can see the price for about what your hobby store is selling it for.
For zim, I would try the same thing. You can get cheap PE zim (no bending) or resin Zim. (i have heard resin is better than the PE stuff.) PE will be about $13 and Resin will will be about, $20-$25. There are alot of AM barrels out there, so you will most likely find one. Again I recommend going to greatmodels.