While essentially the front suspension mounting points are the same on the IQ, the IQR, and the PRO Ride bulkheads (and all the A-arms will interchange with the correct bushings and pivot shafts) the rest is not. Driveshaft, Jackshaft, tunnel height, etc. and their locations can vary by a few inches from the front suspension. So if you are just jigging for the A-arm mount points you are probably fine, But if your jigging for more than that, I would go newer or borrow a friends PRO or Rush in the off season.
Also there should be plenty of insurance wrecks you could get cheap if you know who to ask. I've found a few complete chassis (with a bent tunnel) for around $200, as most insurance companies and dealerships swap to a complete chassis rather than messing with putting a new tunnel on. The bulkhead rarely gets damaged, but gets tossed anyway. Might be a few sitting behind your dealer right now.
Good Luck!
