Have you taken them out yet? I had an ACE bolt seize in badly because of the heat then snap when I tried to remove it, requiring a trip to the machine shop to have them drill it out. The stock bolts are Grade 11 (really friggin high grade tough stuff) and the ACE bolts are 8.8 or something like that.

Anyway, this is moot, you should buy new bolts from the dealership is the best answer I can give. New bolts, new 2g double crush washers (2 per bolt), *edit*and don't forget a new gasket*/edit* some Loctite Copper Antiseize (they sell it in sticks at discount) and torque it properly (40-47 ft lbs) and she shouldn't come loose until you want her to. Used bolts are bad news, they can be worn out and come loose easily. If you want the easiest place to order this stuff from, www.jnztuning.com