sodapopsixtysix posted very nice Remington 870 Marine Magnum with Upgrades on Remington 870 Forum.

List of the Remington 870 Marine Magnum Upgrades:

Remington rifle sight barrel
Remington synthetic youth stock
S&J hi-vis follower
Wilson Combat jumbo safety
Mesa Tactical Sureshot 6 round side-saddle
CDM MOD-C flashlight mount
Surefire G2 Nitrolon flashlight with McClicky Switch and toxic green boot

Remington 870 Marine Stock

Remington 870 Marine Stock

Remington 870 Marine Magnum Barrels

Remington 870 Marine Magnum Barrels

Remington 870 Marine Magnum

Remington 870 Marine Magnum

Remington 870 Marine Magnum with Upgrades and Accessories

Remington 870 Marine Magnum with Upgrades and Accessories