What type of set-up are you going to do? H23 with the H22 head? Or did you mean H22? Either way the M2B4 is hard to come by-because of the LSD. There are places though, but you'll prlly pay $1,000 to $1,500 based on the condition. Good luck!

P.S.-you could always get the M2F4, or other H22/23 tranny and get an aftermarket LSD (Quaife or KAAZ) and have it sooner. My 2 cents