I sat in the back while Ash test drove a Colt Turbo... they aren't bad cars at all. I can see the appeal....
Forgetting money matters, and having owned a Mitsu myself, ok not a ralliart, but they aren't as good of build quality. I don't like them at all. There finish is nowhere near an Opel, even if your Barina is a few years old.
Having said that, with the tech it's got, it's a mad little car... and handles so well. The seats are awesome!
And IMO, thats an ok trade in price on your car. I was offered $6k for mine from Nissan when I got the Lancer - and even though just the base model, a lot newer and dealers say they dont look at mods when working out trade.