[CJay]

Motor:
Systema magnum (but it's a basterd on yer gears)
Guarder infinite torque (awesome)

Hop unit:
Prometheus strike neo with te double airseal support tube feed.

Barrel:
Prometheus eg stainless steel 6.01mm tightbore

Hop bucking:
Systema mid durometer.

Stay away from madbull barrels and hop units. The barrels are anodized aluminium which means wear and tear will occur fast on ur dmr setup and lose accuracy. Hop units are a spin idea but hbe been proven to be very far off standard tm spec values.

I'd actually install a bore up kit with any barrel of 500mm or over or u get into negative pressure variables and u lost any hope of consistent fps and accuracy.

I'd also shoot for 430 fps so an m130-m140 spring ten cut the selector plate in te gearbox to limit itself to semi-only.

Using a MOSFET on this system is a terrible idea due to the heavier spring which means heavy current draw on the motor. Not to mention space limitations.

Battery options are extremely limited. As a dmr u want fast trigger response which is all about the battery motor combo. The motors I mentioned above will work ok in conjunction with a mini type battery but to be honest why waste ur time on a small an underpowered 9.6v mini. LeAves u with 2 real options. Simply go lipo eh uh means u can go smaller or do the best thing and go full stock and use a real mans battery.

Get urself a 9.6v 4400mAh large sub-C battery. Airsoft guns were never meant to run on mini batteries and on an outdoor gun it's not even worth it to run anything smaller. Larger capacity and physical size in a niMh battery means better performance and better trigger response. Don't waste time on an 8.4v as it lacks the oomph the really be snappy on the trigger.

I myself use nothing less than a 5000mah 11.1v 35c lipo. Although I do chew thru a few pistons every season but I get insane cycle speed and trigger response haha!

Seriously though ur battery option is a big part of a dmr so don't skimp. In this case size does count!!!!!!!!