Alpine GPS/HU Integration Quality?

I'm thinking about getting an Alpine IVA-W505 HU (http://www.alpine-usa.com/US-en/products/product.php?model=IVA-W505 <-- I haven't been on any forums in effin' ages, how the hell do you write the tags to hotlink text instead of showing the whole URL again?) and I was wondering if anyone's got experience with that unit, and specifically with the GPS's that dock with it. I'm kind of curious about signal quality since the GPS would literally be buried in your dash. I also read somewhere (possibly Crutchfield reviews, can't remember) that there have been issues getting the GPS and the HU to dock correctly and it takes some people several trades with Alpine to get a pair that will mate up.

Anyone have experience that can chip in on this combo? I'm interested in both the GPS's that will dock with it, the NVE-P1, and the PMD-B200, I'll narrow that choice down a little later.