RE: Savage 3.5 X RTR vs. Savage 4.6 XSS kit
Depends how they package it really. Wouldn't wanna open the easy access gearboxes and discover - GASP - plastic diff housings with 2 bevel gears!!
If you're certain its a full on X platform, and you need the radio gear, and don't mind swapping the engine once you've ripped the 3.5 to shreds, then its a dream come true.
From my understanding the XSS has a few upgrades here and there compared to the RTRs, like the stinger, Dirt Bonz tires and I think a few things in the drivetrain.