I have not done any of this, but as far as what i've seen or what is out there, there are not too many options.

Supercharger pulleys seem to have very little potential but can be purchased from Mina Gallery or Eurotoys:

www.minagallery.com
www.eurotoysltd.com

I haven't seen much about tunes but I think eurotoys might be able to mess with your ECU and I have heard about some place else that does tunes for Jaguars.

I don't know anything about the transmission except it seems to be a very touchy thing and giving it more power to deal with seems like it will shorten your transmission lifespan.

whatever you decide to do, good luck