Have an F90bt that I'm just not happy with it's overall performance (I think my D3 performs better). So a few ?s

920 vs 930 (if I can find the 920) differences? 930 better?

Upgrade from F90. Is it worth upgrading? One of the many things that drives me nuts is that it takes almost a minute for the 90 to fully start up. I needed to eject a CD the other day and I had to wait 45 seconds until the eject button would respond.

I can only comment on the 920...I love it. Seems to have little to no lag at all. Start up takes a few moments but it's not a deal breaker.

the start up time is better. for the most part, the interface is too.

however having a heavily modded F series still gives me a few options that newer stock units dont have

I have the F90 and 920. The 920 definitely starts up better and is the overall best but the only thing I don't like compared to the F90 is with the navigation. The F90 shows you 1-2 steps ahead in your route and displays it on the screen so you know if you need to be in the left or right lane. The 920 doesn't appear to have that and until you get to the .5 mile mark it won't tell you where to go which sucks especially if there is traffic, now if someone knows the fix let me know cause that would be sweet and the 920 would be perfect. As far as the 930 I believe the only main difference is the lack of voice controls and in all honesty I could care less about it but right now on Crutchfield you can get the 920/930 for the same price so I would just do the 920.