Obviously you'll want to test them both yourself, but the general consensus is that the X-25 has an outstanding wakeboard wake and a nearly outstanding surf wake while the X-30 has and outstanding surf wake and a nearly outstanding surf wake. Since you say you mostly surf, I'd say the X-30 is the boat for you if the wake is your only criteria. I think most would agree both boats are good enough at both wakeboarding and surfing that you'd be happy with either one and could safely choose based on which one offers a better interior layout, storage, etc. that fits how you use the boat.
As for your other points... The X-25 is fine with the 5.7 engine. Is it better with the 6.0 or 6.2? Sure, but it functions well with the 5.7. I recently got the X-25 with the 5.7 and was a little worried, but have been pleasantly surprised. The only time I wish I had a bigger engine is when I'm pulling the kids tube as the deep v hull does bleed off more speed than I was used to in turns, so the 5.7 has to work a little harder to accelerate the X-25 out of turns.
Pickle fork vs traditional: Overrated difference. You'll get used to and love either one once you're having fun with the boat.