If you're picking up a brand new V2 LEM then it comes with a heavy Trigger Rebound Spring and a heavy Firing Pin Block Spring.
To run you gun like Tom runs his P30/HK45 then you need to get a Light FPBS. That Part number is 209296.
If you want it even lighter (My preference) then also order the TRS which is part number 209266.
Just GIve HK-USA a call to order these. I think it's 5$ a spring plus shipping.
Here's the thread with instructions for swapping both springs.