As far as I know no company publicly sells and off the shelf kit to adapt a Z33 transmission to an SR. I'm assuming that you want use one because it's a six speed and stronger and all of that stuff. If you really want one run one then you're looking at needing a custom bellhousing/bellhousing adaptor which can cost you some major coin.
Another great option if you're looking for a good transmission to run is a Z32 transmission. The gear ratios are similar to those of an SR or KA but the transmissions are a lot stronger.
Xcessive manufacturing has a kit that I like.
http://www.xcessivemanufacturi...tep=4
Basically you get a plate that bolts to the SR and then bolts to a Z32 Transmission and then it includes a driveshaft and other fun stuff.
Mazworx also makes a kit.
http://www.mazworx.com/index.p...=2759
With the mazworx kit you have to ship your bell housing from the Z32 trans to them.