I dont know about the XFI but I have the Mallory Hy-fire 6 with a built in 2 step. I have mine set up on a momentary button that also controls the line lock. The 2 step has a toggle so I can still use the button when doing my burnout and then switch it on to hold me at the line. I also have the corded buttons going into a 12volt acc. outlet so when Im not racing the button stays in the glove box. I did that more for the safety issue......My wife is a blonde.....enough said!!! lol
84 GT T-top, 306 GT40P 5 spd. Trick Flow stage 1 cam, 1.6 roller rockers, Edlebrock RPM Air Gap, BG Speed Demon 650, Mallory ignition, Full Mac exhaust, FRPP driveshaft, UPR pro rear suspension, Moroso drag springs, Lakewood struts/shocks, SOS anti roll bar, 4 point roll bar, 3100lbs with me!!!!