Is it possible to put dome top pistons in my 04 300m

sure but...mill the head instead..

Adding compression will require premium fuel and modifications to the engine computer's tune. I would NOT do it.

try getting more air in the cylinder to compress... right behind the air cleaner box there is a smaller plastic box. put some holes in it. 1" (x3)devise a airfilter out of some close cell sponge, large enough to not be sucked out of the box. there you have it more volume to compress.