Personally I think there is much of a differnce,
In this highly competative class where even the tiniest things make a difference, I think the E4 has a lot of new features.

- The big Bore dampers are different, yes you could buy them separately
- The space (or mounting hole) for a mass damper up front is a big difference compared to the E3.
- The front kingpins have a different coating and although the E3 had a option to get TI coated Kingpins I think this is a good new feature which improves the front end. And yes you could buy them separately
- The Front end Flex characteristics are different and although this is a small adjustment it can do a lot.
- The rearpod being “stronger” and les prone to tweak is a benefit for the more “common” racers like myself.

Al in all a lot of small things you make it a big improvement if you ask me. You could buy them separately but the you will probably end up paying the price of half a kit. I personally would invest and buy the new kit so I have all the new features.

Regards Robert