Changing spark plugs at 30,000 miles?

[Power4]

After finding out that '07 and older GTs have a crappy spark plug that should be replaced before there's too much carbon build-up I'm concerned about replacing my plugs. I have about 29,000 miles on my GT and am worried that if I try to replace them there will already be too much carbon build-up and I'm going to break them off in the head.

The highest mileage I've read about someone replacing them was 17,XXX miles I think and they appeared to have no problem. If I use a lot of penetration lubricant and give it plenty of time to work should I be fine changing my plugs?

Also, how many people have actually had problems with the plugs breaking off in the head? I know this is a preventative maintenance thing so that the chances of it happening down the road are reduced, but has anyone actually had this problem on a Mustang GT?

 

[GOLDENPONY]

Plug Hell

I had 38K miles on my '06 GT. 6 out of 8 broke off. I broke off 1, took it to the dealer and they broke off 5 more. It cost me $634 to have the old ones removed and a new set of Motorcraft junk 2 piece plugs put in. I *itched enough and got the money refunded by Ford.
I took out the new Motorcrafts after about 2 K miles, threw them away and installed a set of the new 1 piece Champion #7989 double platinum plugs. Car runs great and I sleep better.

 

[o0Dan0o]

I have heard of people breaking plugs at 30k, but I think it was just one or maybe two, so if you're careful you should be ok. Mind the penetrating oil as I've heard too much could cause hydrolock. You could let the dealership do it, that way if they break it they get to fix it, but they might not be as careful if they haven't done it many times... It's still under warranty right?
Dan

 

[Power4]

The car is still under warranty. I'm thinking I may just leave it alone until I have to bring it in for some other repair and have them swap out the junk plugs for one piece plugs. If I let them do it I'll be sure to let them know of this issue and to be as careful as possible. I just don't want to do it myself then have one or more break off and have to tow it to a shop and decrease my chances of it being covered by the warranty or by Ford.