Depending on what power you want to be making you will probably want a stronger diff/tailshaft. I'm using a Hilux rear end with a 3" two peice custom tailshaft making around 300hp and it has handled that no worries.
I'm using a S13 clutch master cylinder but I think you are able to use a standard ae71/ae86 pedal setup/master.
Your firewall will either need a bit of bashing or if you want you can go to the extent of cutting and welding in a new tunnel to make it a bit easier for gearbox/clutch changes etc.
Shifter hole will need to be extended unless you are planning on using a RB20 bellhousing.
You will need your sr20 loom wired obviously, mine cost around $300 from memory wired in.
Mmmm all I can think of off the top of my head any questions feel free to ask