My point is if you want something quieter getting any convertible and putting a pair of bikes on the back isn't going to work. No convertible is ever going to be as quiet as a sedan...or even a coupe. 03 & 04 are quieter then previous years but not by all that much with the top up.
I very much undrestanding measuring db's and I know for a fact that what 1 person is sensitive to another person might not be. 5-10 or even 20db's is not that much and it isn't something most can even hear. If we were talking about 160db vs 200db...then we can have a conversation, but 5-20db....you can't tell.
https://www.cdc.gov/nceh/hearing_loss/what_noises_cause_hearing_loss.html#:~:text=Sound% 20is%20measured%20in%20decibels,immediate%20harm%2 0to%20your%20ears.
Honestly if that is a sticking point with your partner...sounds like it's just an excuse.