1. Go here, type in 1080 Ti and look at the rankings / read the reviews:
https://www.techpowerup.com/reviews/
from best to worse ... I'd stick with 9.7 or above
Gigabyte (9.9) https://www.techpowerup.com/reviews/Gigabyte/GTX_1080_Ti_Xtreme_Gaming/
MSI lightning (9.8) - https://www.techpowerup.com/reviews/MSI/GTX_1080_Ti_Lightning_Z/
MSI Gaming (9.7) https://www.techpowerup.com/reviews/MSI/GTX_1080_Ti_Gaming_X/
Asus Strix (9.7) https://www.techpowerup.com/reviews/ASUS/GTX_1080_Ti_Strix_OC/
Amp Extreme (9.6) - https://www.techpowerup.com/reviews/Zotac/GeForce_GTX_1080_Ti_Amp_Extreme/
Palit (9.4) https://www.techpowerup.com/reviews/Palit/GeForce_GTX_1080_Ti_GameRock_Premium/
EVGA (9.4) https://www.techpowerup.com/reviews/EVGA/GTX_1080_Ti_SC2/
Reference (9.3) https://www.techpowerup.com/reviews/NVIDIA/GeForce_GTX_1080_Ti/
If ya want water, the only one I'd consider "pre-assembled" is the MSI Seahawk w/ EK full cover water block.
The CLC types do cool the GPU but w/o helping the VRM and memory, doing half the job is a waste of time, money and effort. The Seahawk EK needs to be connected to a custom loop or an open loop type AIO such as the Swiftech H240 or H320
http://www.swiftech.com/aio.aspx