Personally, I wouldn't do it and I'd let the dealer mess with it at some valve-check interval which could be a major pain if you need to change one of those shim/ball things. You'll need a radiator evacuation system too if you do it. If you don't have the $300 GS-911 tool, you might need that to shut off the Service Warning at the valve-check interval anyway.
I paid around $700 for the 'check & plug replacement' (4 BMW plugs were like $100 of that!) at about 17,000 miles. I think Meese on here did his and broke a coil in the process with Grif. I think the BMW plugs are some long-lasting ones anyway that are probably good for 100K miles too. That's the change interval on my car now and Toyota dealer insists they will last to maybe 130,000 miles and to leave them alone. He could easily make money changing them sooner than 100K miles, but either he's honest or just lazy. Platinums maybe?