I've seen both and owned the blue head v-spec.
Not much differences if at all any, as far as performance is concered.
Yes it does have silicone in the crank, and inserts and PLA PLA PLA but all these at the end add to costs and offer "not much" in performance.

As for fuel economy if you do read all the threads available on these two engines from this forum and others you will get different opinions.
Other say the speed has more runtimes but others suare by the blue head that gets better.
You can't get a true answer on this topic...yes an estimation on what it can do but not the real thing.
I bet both get excellent mileage but IMO i wouldn't be paying almost $200 more to get the speed.
Get the original blue head...break it in fully (1-2G) and then replace the rod and the bearings with ceramic and you are done for the rest 7-8 gallons and more.