My friend and were wondering what part is limiting aggressive offset on the fenders? Can anything be done about this? Like roll the inner fender lip, like i did on my daytona to run 245/45/17's?

 

There isn't much room to roll the fenders as the center part is very narrow. The suspension arms and the inner wheel wells is what limits the offset for aftermarket wheels.

 

Ahh, makes sense. Thanks.

 

Actually, you would be suprised how much rolling the fenders will help, at least for me. I have a set of 17" Enkei RS6's with a 38mm offset on my p5. When I put my H&R's in, the tires would rub when I had people in the back. To make matter worse I put my subs in, and then I lowered it a little more, because I didn't like the way the front sat higher than the back.
I took a 1"1/4 dia PVC pipe and rolled the fenders. It helperd a little, but then I took the wheels off went under the car and took a towel, pressed it against the inside lip of the fender, then I gently took a hammer and tapped out until all that was left was nice flat surface. Now my fanders sit right on the tires, for about a 2-2.5" drop all the way around and I don't get any rub with people in the back. I gained at least 1 mm of clearance, and now when the car suspension compresses it is just enough to clear and suck up into the fender well. I run 205/40/17 Nitto tires, and -1.2° camber in the back. And that camber number is within Mazda factory specs so I do not have excessive wear in the back.

Although in your case, I don't think it would be enough to clear some 245's depending upon your offset and what-not.