Diff Questions

Hey all been a while since I posted here.

I have had my emaxx for about three years now with a few upgrades, and I am finally considering upgrading to make it brushless. I currently have:

Pro-line Servo Saver
Hardcore racing bulkhead f/r
MIP cvds front and rear
UE center ti cvds, UE idler gears
Xtreme Racing carbon fiber lowered chassis (non-brushless version)
RPM skid plates
RC Raven aluminum skid plates (not being used atm)
Dace 23mm adapters (no wheels or tires yet)

My transmission is currently locked in second gear using shoegoo which has held surprising well for the last couple years. My main questions is since I need to upgrade my diffs and I already have bulkheads, should I get some UE 6 spyder diff kits, or FLM bulkless with diff gears?

I also question sometimes whether upgrading the e-maxx is worth the investment since I estimate it will cost around $800-900 to upgrade it to a brushless machine. For that amount of money I could finish off these three projects:

Tamiya Mini Cooper-Install brushless
Clod Crawler-install crawler chassis and aluminum beadlocks
RC18T-Install mamba

Sometimes I'm tempted to just sell it off and wait for the G-Maxx Revo conversion to be released.