I am currently using Denso TT plugs in my CTS and I am happy with them. These are not "as gimmicky" like the Bosch +2 or +4 or the terrible E3 plugs. They have a good design and I think they work well. Do they work better than the single tip plug previously installed? I don't know because none of us would be able to butt dyno any differences in a sparkplug unless it was missfiring.