hi mate. you've prompted me to make my first post after lurking for a while. sounds like you are in a very similar situation to me. I'm currently looking to purchase a Z, similar budget, and trading in my celica too!
had a look at a UK model at a main dealer the other weekend and had a drive but I'm now leaning towards an import (uk ones still a bit pricey for me)
I'd be interested to know how you get on, so keep us posted!!
I have lots of questions to start asking but i'll save them for another post, don't want to hijack yours.
btw, part ex value offered for my celica was terrible.