I am very happy with the 10 speed in my GT convertible, even with 3.15 gears... no worries about tire spin and it moves very well once it hits 4000 rpms in sport mode or above. I have toyed with the idea of changing the gears to 3.55, but haven't seriously pursued it. Can't help you with audio system advise... I'm hearing impaired.Thanks. Sounds like a focus on the 10 speed with 3.55’s (which I found one with the performance package that has 3.55’s) is the best use of my time to drive. I’d rather have the auto anyway (I know don’t judge me) so if that provides noticeable low end power, this may be a done deal! I’ll live with the stereo shortcomings.