Brian Leask does modify WURs and does a great job - and provides excellent instructions. Be aware that you ought to be ready to adjust it yourself and have an AFR setup to properly do so. The fuel head itself may or may not be necessary - this right from Stephen - and it isn't adjustable (and doesn't need to be) FWTW.
I have both, and once winter eases up, I plan to final tune it.
Right now I'm at 438 RWHP and 396 lb ft tq.....
3.4L, SC heads, 964 cams, B&B headers, K27 HF ZC turbo, Ruf IC. WUR & RPM switch, IA fuel head, Zork, G50/50 5 speed. 438 RWHP / 413 RWTQ -
"930 is the wild slut you sleep with who tries to kill you every time you "get it on" - Quote by Gabe
Movie: 930 on the dyno