It's not a "totally different" suspension, or brakes.
Different driving experience, come on...It's a different driving experience between an LS and a Redline too...But the car cost more because it has a diesel engine and diesel emissions systems which are far more expensive than the standard gas engine. It's not a premium because they made all these changes to make the car 'better' or more premium.
Wasn't aware of a windshield or door seal difference either...Reference?
It's not a different car altogether..It's just a Cruze with a diesel engine in it. And it's a ~$3000 option that will virtually never pay itself back in fuel savings, especially if you have out of warranty diesel specific failures.
EDIT: just noticed you guys appear to be tslkimg about Gen1s also. Which changes things a bit, but not much.
It's still A LOT of money that you're highly unlikely to ever recoup, if that's what you're buying it for. If you're buying it because you're a diesel fan, and you want the extra power, and can deal with the extra maintenance, then go for it. But it's hard to make a case purely on dollars.