Robiwon can speak more to this since he has the kit in hand, but I'm not sure what they could add. The kit has most of the major components and details right. There are many opportunities for super-detailing, but that's adding lots and lots of little styrene squares and other doo-dads that are too numerous and small to produce as a "kit." The sidewalls could use a bit more detail, but replacing an entire sidewall piece for, say, a resin cast seems to me like a waste of a fairly good original piece. I think the best bet would be a replacement main hangar bay -- deeper and featuring the claw gantry -- but the way it's molded into the main hull is going to take some skilled surgery to remove the old one. It's not just a matter of swapping pieces. Someone with enough skill to remove the hangar will likely just scratch build the deeper walls and reuse the bay's ceiling piece. At least, that's my plan when I get one of these.
I think the most likely aftermarket stuff will be a lighting kit from Voodoo or someone else.