I called Antec, as soon as I mentioned the front door and panels the guy said he'll send those out to me. So that is taken care of.
For the motherboard mounts, he knew what I was talking about but said he had trouble visualizing it. So I had to take some pictures and email them to him. I did some measuring, the mounts in my P-180 are 7mm high. I used a Sonata case I have as a reference (all measurements should be the same as far as motherboard mounts and backplane are concerned). All slots and openings on the back of each case are the same. What I found was the motherboard mounts for the P-180 are 2mm higher than those brass ones supplied with the Sonata. I also measured the few brass ones you get with the P-180 and those were 7mm as well.
Again I don't know if this is enough to put a strain on the motherboard slots when a card is installed and secured. But I'd like to be sure so I don't have to go through all this hassle again of trouble shooting, having to RMA and wait.
I do have a SLI setup with two BFG 7800GTX 256MB on my DFI LANPARTY UT nF4 Ultra-D modded in my P180 SPCR Edition, and don't have any problem while installing the cards. I've just removed and re-installed them to see if I had the same trouble than you, and the answer is no!
Maybe you're just a little too hard with your component!