New Rig and EVGA GTX 680 Signature+ Questions

1) I plan on making a rig soon, and am in the market for a prefilled, maintainence free water cooler. I don't want to assemble my own water cooler, and was wondering if anyone could suggest any. Kindly do not tell me to go for any Corsair or Antec products, because as per many reviews, they use cheap quality parts that cause pump failure/ leakage. Can anyone suggest a high quality, long lasting one. I would go for one with a 120mm or 240mm radiator I mostly won't be overclocking, but would just like to keep my CPU cool. My budgets around 125$-150$

2) I plan on getting the EVGA GeForce GTX 680 SC Signature+ w/Backplate, and was wondering whether anyone could tell me if the body is made of some metal, because I don't like plastic . Secondly, will it be possible to bring down the clock speed on the 680 to the normal speeds?

3) Lastly, can anyone tell me if this rig is good for gaming and which RAM should I take?
CASE- COUGAR Evolution BO
PSU- Corsair Professional Series™ HX750 80 PLUS® Silver
CPU- Intel i7 3770k
GPU- EVGA GeForce GTX 680 SC Signature+ w/Backplate
COOLER- Corsair Hydro Series H100 Liquid CPU Cooler
RAM- Its either Patriot Viper Xtreme 8GB [Model PX538G1600LLK] or the G.SKILL Sniper Low Voltage Series 8GB [Model F3-12800CL9D-8GBSR2]
MOTHERBOARD- Asus P8Z77-V Pro
HDD- Barracuda 1TB Seagate Drive
Who makes better quality RAM and is better with serice, Patriot, or G.Skill?

Thanks to all those who reply!