2d system, rpm turn-on

[wrx+]

I have been running the 2d in my 03 wrx for a few months and have just recently upgraded to txs's stage 4. I have been ref. boost to turn on the W/I but now I need also to ref. rpm's to stay out of det. when shifting. Does anyone know the part # for the radio shack switch/relay that will allow me to do that with my Utec? and the proper way to apply it to my system?