The way you're set up now with your 23, the cost would probably be the same in the end to just sell your Parker and buy one of the models with the bracket and rear storage already done. I've heard of brackets being around 5k installed, but when you're done you still won't be gaining a whole lot of cockpit space, or have the built-in storage on the transom. This is just my opinion...and we all know about opinions! lol
I have the 2520xl and I'd really recommend you move up to that if you're really looking for more space. The good news is these babies hold value very well, so your kinda getting what you pay for when selling and trading up or down if you do your shopping. Somebody out here wants exactly what you have, the way it is....
Todd