It's never the wrong time to get DSMlink. DSMlink rocks, I can't wait until the 1g version comes out. At the least, buy an SAFC and datalogger, either blue-screen version will work. Take care of the fuel system with a walbro 255 or the quieter supra pump, a good adjustable fuel pressure regulator, and some 650's.

The (poorer) guys on the Supra boards run their sidemounts until they run out of other BPU mods around the 400 whp level then switch to big front mounts and typically pick up only ~20 hp. A Supra sidemount is more than enough intercooler for an Evo 16g (don't bother with the other 16g's with the Evo 16g's selling for low $500's new). The front mount will work better, heatsoak less, but you can cheap out without losing a proportionate amount of performance.

*edit* I just asked a friend of mine who is on the Supra boards a lot, he says sp engineering tested their sp61 single turbo kit on the stock sidemount and made over 500 whp. Probably heatsoaked the hell out of that thing on a highway run, though.