Botond: To prep the plastic bumper surrounds, both the leading edge and the upper and side pieces (with the side markers in them) really just scuff them with a green 3M scotch bright pad. That is all you need to make the primer adhere. I painted all my plastic pieces a couples years ago on my 318i b/c they were so faded from the sun. If I can remember, I did two coats of primer and then two coats of Black Bumper coating (I got this at Advanced Auto Parts). It is a special paint that looks like the orginial plastic when new. So it is a matte black. It is really amazing what this does. It really does look like new. As you can see by my picture. I did the side mirros too. These are the older style that are matte black and not body color. When scuffing with the scotch bright be sure to get every nook and crany! If you miss a spot, that is where the paint will start to lift. Even if you go body color on the I would still do the 3M scotch bright pad and the primer, then your final color coat as Paul suggested. I don't have experience with the metal bumpers, but I have seen a number of painted ones and almost all of them had the paint flaking off.
I mildly dislike diving boards (they are handy to stand on when I have to reach a high shelf in the garage). What is compromised in vehicle impact protection by tucking the diving boards? How much compromise?
well, the bumpers are _supposed_ to be rated to take a 5mph impact, so I guess you lose the 5mph of impact dissipation you'd have before the impact forces would begin to move into the body of the car. One thing's for sure - you wouldn't want to bump anything w/ your bumper after tucking, or you'd find yourself saying '*uck! Why did I tuck!"
5mph is a slightly brisk walking pace. If I'm getting hit, it's guaranteed to be at a speed of more than 5mph. And besides, if I'm getting hit, the other driver will pay or I shall unleash my fury!
Slow speed crashes are not uncommon. I got hit last year at about 5 or 6 mph. I was in a rental car in a shopping mall parking lot waiting for someone to pull out of a parking spot. They came back and back and back and whalloped me. No (visible) damage to either car: the $30 of modern plastic foam under a flexible body panel system worked well; probably better than the $800 USA E30 oil shock system. What is the construction difference between E30 USA-spec bumpers ("diving boards") and euro-spec bumpers? Do euro-spec bumpers still have 5 mph impact resistance, but just constructed in a more compact way? I'd sure hate to take even a 5 mph impact directly on the frame/unibody.
Up to '89, I believe the U.S. required all cars to have bumpers capable of taking an impact up to 5mph (not sure if there was a requirement of the bumpers/shocks themselves surviving the impact). This constraint was relaxed, the new standard becoming 3mph, and thus the different bumpers on later E30's. I don't know what the euro requirements were, or if it varied from country to country, but I would figure the euro bumpers would likely be 3mph. Just a guess what the euro deal was, though.
If I recall, Racing Dynamics was recently trying to unload some of their E30 rear valences (among other things)...and they were cheap, too. I'll see if I can find a link.
Yeah, that's the prices they have on there now, but if I remember correctly, these were much, much less than that. Like <$200 for a rear valence? I'm still looking for the link I had. EDIT: Here we go. Don't know if these prices are still good, and it looks like the E30 list is smaller than it was: http://www.racdyn.com/Localized/NorthAmerica/2009_Sale/2K9_Sale_Detail.cfm
Yes, when I had originally seen that list there were several pieces under the E30 section that may have worked, but evidently they sold them off. Sorry man...
