To cut, or not to cut? That is the question.

[68Stepbed]

I want some honest opinions. You won't hurt my feelings. Below is a current photo of my 68 stepside. I'm currently in a position that I could care less for power parking at car shows. For the past couple years, I've been more interested in events where some sort of driving is involved(Power Tour, cruises, autocross, etc.) In the autocross world, where I'm most active with the truck, wider tires are better. The problem is the rear stepside fenders don't allow much room unless some tubbing is involved, which comes to my dilemma. I'm having a hard time making the decision to cut the bedsides to install tubs. The reason is my bedsides are in near perfect shape and stepside beds are somewhat hard to find in good shape. I currently have 17x9.5 wheels with 275/55/17 tires, and they rub the inner bedsides bad enough that the paint is blistering. I really want to run 18x12 wheels and 335 tires, but I really just don't know if I will hurt the value of the truck if I cut the bed up.

What say you guys?