Dm4 doesn't need lubing every tourney- regular maintenence - as with any marker keeps em singing- very very happy with mine- i went from a NYX trix to a dm4 and i'm blown away by them- timmys are very nice. fast too but seem 'fragile' in my hands.
Efficiency wise - check out the ghetto top hat mod mentioned on every yank paintball forum, for the cost of insulation tape you can increase your efficiency.
You will feel the difference tho when moving from an ego- the increased weight will be noticable.
On an extra note- both timmys and Dm4's are now upgradeable with new musashi 3 chips (dm4) or boards(timmy) to millenium rules (capped semi @15bps) as well as including nxl mode and uncaped semi auto.