I was going to get a Lotus Elise. I wouldn't touch a Lotus, (well I might touch a toyota engined one). Have a test drive see what you think. They're very awkward to get in and out of with the top on. They leak...alot. Not much equipment (that dosn't bother me that much to be honest).
They feel very much like a kitcar, very raw, noisey. All that being said, they're supposed to be top of the tree handling wise, I have heard alot of people slate the handling...no idea why, the early ones are very prone to oversteer, which I'd think was a good thing, maybe that's what puts people off...
The Impreza...well...you can't get much better bang for your buck, they're very fast, reliable etc etc. Best thing of all very modable.
I'd knock the asta in the head...the Scoob and Elise are proper sports cars (from different corners of the driving spectrum)...the Astra is just a normal hatch with the roof cut off and a quick engine bunged in
At the end of the day it's your call