Heres a few differences I know of off hand.
1) C'dale re-designed the air box from the original version. C'dale calls it the Max-Air box. The E model no longer has the air filter behind the front number plate. The airbox was made bigger/better under the seat so they were able to eliminate the one at the steer tube. This is good because the FI gets more air with the new system. This is probably the biggest performance difference.
2) The X440s still uses the old check screws to determine oil level in the frame spares and tranny. E has an actuall window on the case to look through now. Makes checking oil a lot easier.
3) The E has a juice clutch, which adds performance and about $200-300.
4) The E seems to have a different exhaust system. The X440S has a FMF power core exhaust stock. I don't know what the E has.
5) The E obviously comes with the lighting system.
6) E has different plastic and graffics.
7) From what I understand the changes to the air system allowed them to move the radiator up higher on the bike making them less vulnerable to rocks and bends from crashing. Take a look at the bikes pics on their website to see the difference.
8) The X440S comes stock with tons of goodies. Suspension is the same. It has aluminum bars, steel braided break cables, talon sprokets and so forth. Here's what I think C'dale did to make the price different. C'dale had some old frames so they put them all into the x440s model (does not have the Max-Air box). They probably also had some of the old engines without the oil view window (other than that their the same engine). They then put a new exhaust on the E and put the 'old' exausts on the x440s.
If you look close at the pics on the web site you will notice that the frame spars where the oil fill is in a different place behind the shroud than the x440s. If you compare the two pics, the new exhaust is double all the way to the silencer area. On the x440s exhaust the two headers connect right after exiting the cylinder. And if you compare the pics the rad is noticeably higher on the E. These are the noticable differences in the so called 'entry level bike'and the higher models. The biggest differnces is the Max-Air box, the exhaust, and the rad is higher. The higher models may have better wheels and bars and have of course the juice clutch among other goodies. You'll just have to decide if the differences justify the price. Also, if the x440s is already this good imagine what the X440 is going to be like. By the way all these changes are the same between the x440, c440 and the E440. Anyways, I hope this helps.
[ December 31, 2001: Message edited by: MADEINUSA ]