SSA= SSAutochrome manifolds. Lots of people have been going with these lately despite numerous complaints about the quality of their workmanship and materials. Bottom mount means the turbo is mounted on the bottom of the manifold, facing down instead of sitting on top facing up like a lot of other manifolds.
JGS= JGS Precision Turbo. They make (and sell kits for) what I beleive is the cheapest manifold option for the KA. It's a simple log type deal that you can customize or have built complete. Their website:
http://www.jgstools.com
T2X = Any T28, T25, etc... the x is a variable like in algebra... He's just saying any manifold will work as long as it has a flange for those turbine sizes.
Basically to answer your question, cosmo is right. It doesnt really matter what manifold you get as long as it has a flange that fits your turbo (a ball bearing T28, according to s13chuckat if that is right). Any manifold will FIT, I mean... there are various other things you need to look out for such as clearance issues with power steering, brake master cyls, steering rack w/ downpipe, etc etc etc. Also some people prefer equal length runners over a log style manifold because of the better flow characteristics... Equal lengths are more expensive, however.
Good luck man!