What type of plugs are you buying? I believe Bosch plugs are pre-gapped. If you are using one of those gapping disks, then I can see why you would want something more accurate. In the past I used the type that has different thickness wire hooks to it. It sort of looks like a "Chinese star". It really doesn't take much to bend the ground electrode on a sparkplug to adjust the gap. Again though, I think Bosch plugs are pregapped. NGKs are another brand that come pregapped. I am sure there are others, but can't think of them right now.
1994 MB E320 Coupe (199,500 mi)
1992 MB 190E 2.6 (173,000 mi)
1983 Porsche 911SC (148,000 mi)
2004 Volvo V70 2.5T (198,000 mi)
President of CT/Westchester Section