With all due respect, have you visited the thread I linked to? Did you miss the parts about keeping the stock heat plate and fan?
I understand people's reservations about doing something so unorthodox to what is often the most expensive component in their system but I feel these reservations are unfounded. The risks of AIO watercolors have been reduced to virtually 0 and this mod requires less modification to the GPU than most aftermarket air coolers, all the while being easier to install than those coolers and CPU heatsinks IMO.
People have been doing this for about a year now with hot, high end cards. I've been running two GTX 470s in SLI, notorious for their heat, power consumption and, like all reference cards, noise, for four months and haven't encountered any issues, including when running Furmark (not more than 15 minutes as Furmark will blow almost every card) or BF3 with all settings maxed on a single 1920x1080 setup. To my knowledge there hasn't been a single user who has made a disastrous mistake while performing the mod nor anyone who has blown their card/a VRM afterwards.
Regarding price/wasting a GPU:
An AIO watercolor like the Kuhler 620 or Corsair H50/H60 can be found as low as $40 on sale, regularly at $50 on sale, and $60 at retail. This is a lower price than most aftermarket air coolers. A bracket can be purchased for ~$12 for those who desire a more finished look.
This mod
requires no modification to your GPU - all you have to do is remove the stock shroud (clipped on) and heatsink (four screws in most cases) and you're done. This is actually less than you have to do for most aftermarket air coolers, many of which do require you to void your warranty in exchange for their own lesser warranty that will often not cover the cost of higher end GPUs.
To address your VRM concerns specifically:
First, with "The Mod" the GPU can be kept in stock condition - there is no actual modification done to the card. This means your warranty is still in tact. Moreover, it means the stock heatplate and stock impeller fan that came with your card remain intact and can be used to cool the VRMs like they would with a stock card, only the fan now gets to run at a significantly lower speed as it no longer has to cool the giant heatsink attached to the GPU die.
Second, as many non-reference users have done in the linked thread, heatsinks can be thermal taped on to the VRMs for about $12. For most this is adequate even without a fan, but some users (it is an overclocking forum) like to overvolt their cards, so they find the fan addition a useful precautionary measure.
Third, I've been running my 470s in SLI without a heatplate, heatsinks, or a fan for about three months now and can max out BF3 for hours. My VRM sensors have only turned off my cards when running Furmark for more than ten minutes, which, again, is a popular way of blowing VRMs and the most excessive stress test I know of for a GPU.
Regarding noise the difference is dramatic when compared to reference cards. Impeller fans are loud and not very effective. On reference cards they are pushing a ton of air routed by the shroud into a tiny space with a lot of heatsink in the way and all pushing out of the tiny slots in the bracket - as any user who owns (and makes use of) a high end GPU knows this creates the infamous jet engine sound. With my 470s the fan would reach 85% on load to keep the GPU cores below 90*. Some reviews would cite this as about 70db for the GTX 470 - that is a ton of fan noise/a lot of fans.
The delta for an air-cooled card is probably between 45*-70* on average. The delta for a watercooled card rarely hits 40*, typically floating around 30* for a non-overclocked card. This means that far less airflow is needed to cool the radiator than is needed for the heatsink. Given that the watercooled temperatures at load are typically 30* lower it looks even better for our poor overworked fans.
In my application I saw no use for additional fans, I just zip-tied the radiators onto my AP180s running at 6V (intake in my FT02) and that was plenty of airflow to keep my 470s below 60*. Currently my cards are bare naked - no heatplate, no heatsinks, no fans pointed there way - and the VRM sensor only turns them off when I try to Furmark for more than a few minutes with my fans at 6V (again, a good way to fry your card). If I run my fans at full speed I can Furmark for 15 minutes, which is actually a little longer than I could with the stock cooler (about 13 minutes). Of course I intend on reattaching the heatplate and either the stock fan or some NF-B9s I picked up once I decide which bracket to order (can't decide which fan I want!), but that's just for piece of mind I guess.
Again, I understand the skepticism, but this is quickly becoming a well-established cooling method and the results speaks for themselves. Actually,
Asetek,
Thermaltake, and
Silverstone have all been producing these sort of products for years (Silverstone's passive external solution looked especially nice), but given that they cost almost as much as a full custom loop they didn't find much space to compete. I really wish I had used my phone to measure the sound before and after but I thought of it too late :/. Will post some "after" results later today though.