I run a Procharger and I have had zero problems with it and I have put 14000 miles on the kit. Radix will give you a lot of out the hole torque which you can use to your adavantage with that all-wheel drive and its more of a buy and install and you ready kit. Were as the Procharger you will half to get tune and buy bigger injectors. I would also look into Turbo's to those kits have a lot of potential in them and can make some very big numbers.
2002 Red Chevy RCSS (engine mods)- 05 5.3L, Procharger P-1SC 9lb.pulley, 80mm BBK TB, TB By-Pass, 38lb. Inj., AlkyControl Meth Kit, ASM L/T's, Magnaflow X-pipe, Borla's, FLT Level 5 4L65e, PI 3000 Stall, B&M Tranny Cooler, 3:73's, G-80, E-Fans, 160' Thermo. Custom Built Intake with K&N. WideBand 02 Sensor, DIXIE TUNED.