okay, please give some help to a swimmer with a LOT of room for improvement! Please explain the differences to me between the three of these.

I am assuming the T1 is the top of the line. But where to the DOS and TRES fit in to the equation?

Also, I only plan to buy ONE WETSUIT for the next 10 years or so. So, I am willing to consider making the purchase count if needed.

I am considering making a purchase before Gulf Coast, and am just not sure which to consider buying. I do not own a wetsuit at all. Thanks!