Turbo runs much cooler, since it's now getting lubricated both by oil (which cools it down as well), and washed down by water (coolant). Coolant temperature is a constant 180-190F, so that means way cooler than the temperature inside the turbine, and cooling effects are excellent. Some people speculate that turbos that are both water and oil cooled last twice as long, compared to oil-cooled only....but that might be a little bit too enthusiastic of a claim. I would definitely opt for dual cooling, if it was an option (and reasonably priced). Stock MKIV turbos are both water and oil cooled.Ray745 said:what are the benefits to having a watercooled turbo?