What to wear if wetsuits illegal?

Not to hijack the thread or anything, but I think the OP's question has been answered well...Whatever you plan to race in is my advice too. Very difficult to put anything on or take anything off soaking wet.

But what is a speed suit?? I've really only seen them used in Kona, but have always wondered what they are/their benefit. Buoyancy? Speed?? (I'd assume by the name)

It's a way to cheat legally...

People down here in FL wear them a lot because they're legal in water above 82 degrees.  They definitely have a speed benefit.  I did a 5K swim last weekend and one of the ladies who passed me toward the end had no kick, her form was no better than mine, and her cadence was no faster, but she was scooting along pretty well in that speedsuit.  In the pool, I usually lap her on the longer sets. 

I think it's similar to the difference between a tri bike and a road bike.  There's some advantage to be had. 

Now we wait for the real experts to explain...

...or it could encourage people to swim over you?

I have the exact same issue. Im going to have to wear a wet suit for confidence I think as it my first big OWS, the only thing the organizers are saying is - 

As per USAT rules, wetsuits are allowed if the water temperature is below 78 degrees. Between 78 and 84 degrees, age groupers may wear wetsuits but are not eligible for place awards.

Which Im ok with as I really wont place anyway.