due to a molded swim platform rear thru hulls are not an option and I need to keep noise levels down.
Is there such a thing as inside mufflers in the event I decided to run thru hulls out the sides?

Depends on how much room you have, inline mufflers are available.

yes.

I believe wellcraft used them back in the mid/late 90s on their 26 and 29 models. They were these big fiberglass canister looking contraptions. They worked well to quiet the engines. I don't know the engine/cam profile you plan on running but I've seen some guys with moulded platforms use short risers with 90 degree stainless elbows and couplers to offset the exhaust tips lower/further apart width wise and still puts the exhaust semi above/below the water line. It'll be quiet (not silent but definitely quiet) while off plane and then when you get on plane it'll be loud like normal. I'm not sure if that's what you're looking for or not.

thanks guys

I have installed plenty of inline mufflers for boats that have side hull thru exhaust like your Crownlines, Sea Rays, Cobalts, Four Winns and so on apps. No problems at all and they do cut down the rumble.

Most of the installs the inline mufflers went inside the 4 inch wet exhaust hose portion. I wanted the inline mufflers to stay put (no movement inside the hose) so externally around the wet exhaust hose I installed 4 hose clamps to help secure them from movement internally.

No question is too dumb!

DAmn I wish I could remember where but in the last 2 weeks or so somebody posted piks of that welcraft inboard muffler exhaust setup. it was a thread about 2 different boats he was looking at, one was a smaller scarab.

I believe it was 25 outlaw vs 26 scarab here was the boat pictured.

http://www.powerboatlistings.com/view/30031

And the mufflers Boom!

Dude, you rock!! thats it!! With advanced alcholziemers I dont remember chit these days...