Thankyou therenee...my parents really love the shower...I came up with the in-wall cabinet idea when I remodeled my small bathroom in my home. I even made a recessed towel rack on it because the bathroom was much smaller...it looks like this: At my parent's home, we put in a 2x6 wall there instead of 2x4, to have more usable space inside the cabinet...at my house, I still had more room than the newer homes, because of the old lumber that really was 2x4 and because we went with a little bit thicker sheetrock (5/8) on that wall to help with sound insulating

Most manufacturers recommend 100% silicone bath and tile caulking in corners. ( no grout ) I have had great results with epoxy grouts if you can find your color selection. A bit more labor intensive but well worth it. Check with a local tile distributor. Difference between sanded and unsanded. For residential applications, siliconized latex is more than sufficient. As for the epoxy grout, it's my opinion that with a few specific exceptions, in residential installations, it's expensive overkill. As for differences in the grouts, those of you who aren't familiar with them, you can check it out in the FAQ's on the gallery side of this forum. As for Colorfast and Mapei, yes, I'm familiar with both of them, and the only times I've ever had problems with Colorfast's caulkings was when it was old. I've yet to ever see what I'm seeing in the pictures up above.

If water got into the curb, it'll do it again once the curb is replaced, and it'll most likely be even worse, if you don't take out the pan, and about 18-24" all the way around the walls, and completely redo the pan. The only way to know for sure is to take it apart and see if there's water getting at the framing. You MIGHT be able to see it if you take the tile (or whatever) off the OUTSIDE face and strip that down to the studs, but that's not a guarantee.

Sorry I didn't get to it before this. It was a real long day today!! You're right in your assumption that the grout will now be darker than the caulking if you enhance it. Have you looked at other grout manufacturers? Mapei's Mocha and Malt both come to mind in that same range of color.