Spacers aren't a big deal. They're run on autocross cars and off-road trucks all the time. They're just like aluminum rims, you have to periodically check them for the correct torque. That's it. And really, once they've been properly torqued the first time, and then again after about 100 miles, they usually don't require much torquing. I've run them on both cars and trucks without issue. As far as the spacer goes for the rear, your A-body rear, stock spring location, and disks mean you really need to end up close to 0 offset. Maybe a little on the +offset side of that because of the slight increase in track from the disks, but that extra offset is only 1/8" so really just +3 or +4mm. So, whatever the advertised offset is you'll need that size spacer. +35mm offset? +35mm spacer. The large, stud equipped spacers usually start at 1" and go up in 1/4" increments. So 35mm is 1.37", but if you get a 1.25" spacer (31.75mm) you should be close enough. If you're going to stick with 245's all the way around you don't need a 9.5" wide rim. 8.5" or 9 would be fine. Not sure what you have for UCA's in the front, but the wider rims don't usually clear the stock UCA's at full droop and lock. Even my 18x9's didn't, and they have 35mm offset that I run on DR. Diffs 13" rotors. I'm running 3mm spacers in the front now, so 32mm. And I still have a little room to the outside, so you can probably run your 245's with as little as 18 to 20mm offset, which would give you more room for the UCA. Personally, I'd try to go 18x9" with 255/40/18's. The problem with 245's is the 245/40/18 is only 25.6" tall, and the 245/45/18 is 26.7". So you need 245/40/18's to run square, and that's a little short for the rears.. The 255/40/18's are 26" tall, which is just about perfect to run front and rear. For the PF01's, I'd get the 18x9's with a 35mm offset. You'll should be able to use a 1.25" spacer in the back and clear. In the front you may need a small spacer, 3 or 5mm. You will want to check your clearance on the UCA's, I had to go tubular to clear at full droop and full lock. You could run either the 245's or 255's on those. Also keep in mind you will still need to either have the hubs machined to clear the wheel hub bore, or have the hub bore opened up. Dr. Diff's rotors still have a 2.7" diameter hub, and that won't clear the hubs on the enkei's. They start at 73mm, but neck down to 2.5" (63.5mm) for the wheel cap. I had my RPF1's bored to 73mm straight through. No step, and that way they'll clear the 11.75" mopar rotors as well. I won't be rotating tires though since I have a staggered set up. If I were rotating I would have the hubs machined so I didn't have to make wheel caps for all 4 rims.