I'm running basically the same combo as your car...
I run a 3.55 rear gear and like it a lot, except on long trips...
Seems the engine combo I have is 'happy at 3100 to 3300 rpm and that equates to about 72 mph... I ran a 125 mile trip Sunday to a car show
(see pic's at:
http://community.webshots.com/album/384945224IqjTtC

Got 16.8 mpg.... Not too bad...

4.11's were fun...in town only...

Hope the info helps...
Jeff