What years is the #6 coil different? Mine is a 99 and they are all exactly the same.

98-04

I think one boot is shorter.

It's 2000 - 2004 that has the oddball coil. 98 and 99 use 6 identical coils.

Yes, it 2000+. The wire is a little longer than the rest. If you stick one of the shorter others in #6, you can get random mis-fire code.