Its a replacement valve, hammer, volumiser and lpr cap that lets you set your LPR pressure stupidly low, and lets you set your firing pressure to be as efficient as possible.
People say the DM4 has alot of kick compared to a newtoned angel/G7.
Yes its available for the Euro...
Price £110, you do get alot for your money though.
RE the LCD and upwards:
I would expect it to be cost prohibitive.
If they manage to move the LPR to the battery side and make the board work off another battery, they still need to supply you with a ram that can work at lower pressures.
My guess is it will be for LCD'03/Ir3 and upwards, and even then its gonna be tricky!!!