Panache,
I share both passions--I've attained 4 kilts and 6 sporrans over the past two years, but oh...I was so addicted to boogie boarding when I lived in So Cal! And for my 50th b-day I made a special trip back to LA to play in the ocean. Here's why I say "go for the wetsuit"
1. Experience life fully--you have enough Scots attire to enjoy all the highland events and hiking around where you live, but you'll be limited in your ocean sports without the suit.
2. I LOVE Santa Cruz (sorry I've neglected to look you up there) and if I lived there I'd probably develop a set of gills.
3. Catching good waves is a total high, and there are no side effects (unlike,say, whiskey)

With all that being said...make sure your suit and fins don't make you look like a seal! And if you wonder why...go down to the little lighthouse museum on the overlook point and check out the board with the great big teeth marks in it. We love having you on the forum, so avoid those big whites

Finally, remember not to mix-up language conventions. "Dude" and "gnarly" don't see quite as appropriate at highland games