Someone would probably go to look at a car if you find one, or at least post it up on here and we can have a look and tell you risk points and things to look for.
You say you don't have a lot of time, but it's a lot of money, you're really saying you want an easy answer?
will the insurance be high?
Yes. Depends on your age and location though. UK spec is generally cheaper to insure.
What is the mpg average for non turbo?
Both NA and TT will be about 20mpg.
How does it do regarding current emissions regs?
If the cats are in it'll be fine. 1 cat removed is normally OK as well. Both cats removed and you may fail an MOT. Why would you want to de-cat? Search BPU!
Are they expensive to maintain?
Yes. Think of it as a Supercar and you'll be OK.
Any reasons NOT to buy jap import?
Nope. Apart from insurance.
which is better -manual/auto?
Up to you. I had a manual, my next one will be an auto. Drive both and see.
I think they are rear wheel drive - how are they in snow!
BAD! Although I've never tried it, I wouldn't want to.
Was there a good year of manufacture- I would like aero and air con?
AFAIK they all have air con, there are only a few aeros about - I'm not sure what specs are available in aero TBH.
Most important - any know problems to look for?
They're pretty robust, mostly check for blue smoke.