The injectors for late model S4 TII's and S5's are identical impedance and size wise. Like stated above, you need the S5 LIM for the FD UIM conversion, but I am not sure why you want to make it harder just yet. This is something I would personally save for a weekend of fabrication.
Front mount intercooler systems can be built on the cheap, I'd take a peek at
www.corksport.com for their kit. It is cheap and effective, plus it looks nice. But the TMIC should work just fine as long as you have a TII hood, unless you plan on pushing some serious boost then go FMIC all the way.