Posted 30 November 2012 - 11:58 AM
It sais right there in the upgrade panel it's 40% more efficient and takes up 3 slots, the rest is up to you to work out.
As a rule of thumb if your mech build needs more than 32 or so single heat sinks to work properly you probably won't have enough crit slots to do it with doubles, as that's about the limit of what a DHS build with a decent amount of weapons can do, in pretty much any other case doubles are better. Energy weapon boats with a really big engine can get more out of DHS but they're the exception.