I just got mine off of WildAlaska here on the forum myself lol .
As far as do's and dont's goes ,
Do clean the gas cylinder with a solvent and the brush ( you did get the brush didnt you ? ) every time you shoot it . HK as well as others make scrapers for the cylinder if you get a carbon build up ( you shouldnt if you clean it properly , but none the less it is an issue ) and in fact hk shipped them as part of the p7m8 kit so you might look at picking up a properly fitted scraper ( dont grind a screwdriver down yourself lol ) . If hk is out i know a guy who makes and markets good ones so drop me a pm since i wont advertise him on the board .
Dont leave oil in the cylinder , or on the gas piston since it will just burn to carbon that will gum things up and create more wear . Dont shoot Lead ammo , use only jacketed ( between the poly rifleing , and the gas port Lead ammo is not a good idea.
To remove the grips , take the screw out , lift on the part of the grip that protrudes along the frame while pulling foreward untill it pops loose , its a knack and does not take a lot of force .. force a grip off and you ruin it ( at least eventualy ) .
Dont set around manipulating the cocking lever and releasing it ( gripping and de cocking the gun ) without dry fireing since some folks who have report parts breakage within a few thousand reps . ( Dry fireing does not seem to hurt anything , just reports of breakage with repetitave consistant cocking and de cocking ).
As a final note Wild just ran a pretty good sale on holsters both IWB and OWB that are made for this handgun there is a thread here , or contact Wildalaska if you need what looks to be an affordable quality leather holster with a reasonable wait time .