Good review,
I think you're having a problem with the bumpers though because you're putting it in all wonky...
You're putting it in button sides last, possibly causing stretching of the top part out, causing the earphone hole to stretch out, and you're sliding it over your buttons, causing possible misalignment and POSSIBLY (not sure, but mine are weird because of the fact) damaging the home/volume button (mine is loose because of the SwitchEasy Nude...kinda hard to get off my phone)
Rule of thumb: Buttons in first, I have no problems with alignment and such with my DX bumpers, and I got all of them (except black)
I don't know if this helps in any way, but it was always a rule when I used to review cases for the iPhone 3G (since then, retired from reviewing =P)
Keep up the great work