Got a couple questions:
1) Does anyone have the exact dimensions of the mounting plate for the Ultitube D5 Pro? I got the fan adapter kit, but want to cut an additional plate to offset the mount point in my case, and need to know the spacing for all the screw holes.
2) Are there any instructions out there on how to properly mount pump/res? I took a best guess at things, but not sure if I really got it all right. As well, I've got a left over white silicone piece (the horseshoe shaped one) that I have no clue on where it goes or what it's for.

I partially understand what you said, but maybe I should explain what I did and you can agree or not on whether I did it correctly. Firstly removed the bottom plastic piece from the thicker silicone piece, put the 3 angle-headed screws through that facing downwards, and then replaced it back on the silicone/pump. Next used the 3 plastic spacers and screws (2 long + 1 short) to mount the backside of the pump to the L-bracket, with the 3 downward screws going through the bottom of it. Secured all 6 with nuts (was surprised how securely the bottom screws tightened given there was no direct pressure on them to keep them from spinning while tightening). I then mounted the 4 rubberized screws to the bottom of the L-bracket facing outward with nuts. Finally, I attached the 120mm fan mount to everything by using screws through the 120mm mount into the rubber screws holes.

Left over was the smaller silicone piece, as well as the flat-X plate. Given your descriptions, things sound right. It also sounds like I could use the X-plate as a template to measure where I’d have to put screw holes for the bottom of the L-bracket. And to make sure my understanding of everything is right; if you’re mounting using the X-plate on the bottom that would mean that the pump/res is really just “floating” on everything, and that it actually doesn’t have any hard mounts that would prevent it from moving?