...of a problem removing my plugs at 60K. If you remove the airbox and the battery & tray there seemed to me to be very little problem in accessing the plugs. Not compared to some other memorable jobs I can recall: the PCV on the SVX was an SOB, the belt tensioner on the 420SEL required that I fabricate a tool to loosen the bolt, water pump on a Fiesta required that I ground down the bolt heads to get a box wrench on them, etc.
Only problem I had was not having the PERFECT length extention, so I went crazy and bought another 1/4" drive metric Craftsman set at Sears for $10 (on sale as I recall).
Plugs and boots came off with no problem: anti-seize & dielectric grease help. I used the regular Bosch platinum plugs and they were $1.49 each. No gapping, BTW!
100K miles is way too long IMHO to leave any plug in an aluminum head
CHEERS!