Another thing I might add is that you really need to handle and shoot these guns. It sounds cliche and some people repeat it without understanding why?
For me I found out by shooting the g19 that I much preferred the aftermarket Vickers parts. I also found out I needed stippiling and rounding the underside of the trigger undercut. Plus I want the Gadget, but there is not time table on that yet.
None of this is a big deal and these are very common upgrades. But for me the HK p30 LEM did not need anything other then real night sights. I wanted a gun that I could get and really not have to mess with aftermarket stuff and just shoot it. Parts have not been a problem for me as I have spare springs and such. Plus you already have some experience running a HK with similar controls.
Ps: any gun you are going to get most likely will need good aftermarket night sights.