Some questions on underbody stiffener plates for 67 convertable:

(1) Mine's gone. Should I replace it? Is it worth all the added exhaust hassles?

(2) If I do replace it, how do they mount? I've seen photos of replacement plates with six large holes. Are there some sort of rubber mounts? I've got the six threaded bosses on the underside but the threads are pretty much gone. I will either need to drill and tap oversized holes or use nuts and bolts.