I once tried using a spool on my EVO2, only because I lost one outdrive on the 1way. The acceleration is the same as the 1way plus i got more brake. I also noticed more abrasion on the front tires.
I only got to try this once as I got an offer from somebody for the evo2. Sold it. Now I'm back to my EVO1.
The Evo2's fine except that the chassis I got second hand is starting to get really worn on the rear of the chassis. I also had problems reducing the suspension slop in the front.
My EVO1 does not suffer from this much. I also notice that the front uprights and knuckle arms last longer on the EVO1 than on the EVO2, due maybe to the support that the upper arms lend to the uprights.
I also find the EVO1 a lot lighter. However I lost the ability to adjust roll centers and adjust the wheelbase. I managed to free up the drivetrain some using some washers to jack up the rear gear case. No way it can spin more than 2 seconds though. Maybe one second, that's all. (drooling on the YOK SD)
The most common reason of using TA04 arms is to be able to straighten the dogbones so it is inline with the outdrives. This makes the drivetrain a lot more efficient. HOwever you might exceed the legal wheelbase limits and would have to cut new wells for the wheels.