never knew they stopped making the bottom mount ! that's lame. ...also, blowing out metal gaskets? wtf are you doing to do that? lol. I've blown tons of outlet to downpipe gaskets, but never a t2 flange one. Not saying it doesn't happen..just never thought of it.
anyways, if you wanna stick to jdm brands, I think the HKS one is still in production. some advertise it for s14/s15, but I'm sure it would work on an s13sr. Problem is, if whoever you get it from doesn't have it in stock, then you have to wait for it to be built. Kind of a pain, but you get to brag to people at shows about how long it took you to get it