As others have allready said, have a look at a tadao chip or board.
The only bolt upgrade I'd recommend is the hybrid ebg bolt guide, you can field strip the bolt and it has a efficiency "ring" (just a fancier top hat tape mod).
On Barrells just get a decent big bore barrell most of the kits are ok but because the DM uses such a low pressure on the bolt if the fit is too tight it won't shoot.