Are 3.55 gears a good choice?

Your not going to feel much of a gain and the ET clock will show it as well.

Exactly, if you have 3.23 now and you want that more seat of the pants feel then go 3.91 or numerically higher. I run 3.55, and I have another 489 case I'm going to set up with at least a 4.10 gear for some mild strip.