Does the E4 suffer from the frequent gear stripping that the E3 has?
If you find yourself challenging your tracks barrier constantly, I'd recommend a belt drive.
I use to drive the Evo1 and Evo2 and had to give up on both because I keep on ruining the bevel gears with my novice driving. I wish tamiya will sell a ring AND bevel gear combo like Yok does. I think the bevel gear is the main weakness of the shaft driven cars. If you drive well enough to avoid crashes the go with the shaft drive.
I don't have money for either car