Can confirm that Evo OZ / Enkei wheels do fit very nicely with a slight guard roll on the rear, especially if lowered. Bore is the same, Evo 5 (silver) wheels require square shouldered wheel nuts and washers.
Both photos at stock ride height, 17" versions of both wheels
POR15 is a good choice, it's tough, converts any leftover rust and protects from abrasion well
DO NOT get any on skin or clothes as it WILL NOT come off without the proper nasty solvent (Guess how I learnt that one!)
Another option is regular spray paint, a good undercoat and then a top coat...
Very brief considered finding an 4WD version as they do come up for sale here, but they're a lot heavier and with no real benefits for what I wanted to do :) Plus the 4WD models are all high compression FS-ZE powered, which probably wouldn't like 9psi stuffed in it :D
I think the floorpan and...
I can't speak for the smog requirements, although removing the VICS was a fairly common mod back in the day
The little bolts should be a metric fine pitch thread, possibly a M3 or M4. You miiiiiight have luck at your local mazda dealer, otherwise it might be time to hit the scrap yards...
Ooof :( hopefully the lower radiator isn't damaged and radiator is ok? ( and of course hopefully no one was hurt) With a bit of luck the upper radiator support can be pulled straight and the damaged panels replaced 👍
You can drive the car without the intake as the all important filter housing...