No matter how much you do to the chassis of your pro touring machine, there is still only so much tire you can fit under it and still be able to steer with the kind of geometry needed to quickly travel around the road course or autocross. The solution for covering those big tires becomes a matter of personal preference and style, as well as what car you have started with. Some cars, like Datsun Z cars for example, have a ton of bolt on simple flares available that work great. Unfortunately for some of you the choice is going to come down to skill, style, etc. Do you go widebody and widen an entire fender or quarter panel? Do you just build a flare? A little of both?
The choice is still going to be up to you, but here is some instruction from Lazze on how to make yourself a set of steel fender flares with an inner lip and the whole deal. They may not be exactly what your project needs, but they show you the principles and how to make some of your own with the right tools and practice. Check out all three videos below.