Aye - watch out for insanity setting in!!
I searched for nearly the whole of last year for one and couldn't find one even remotely good.
Seriously though - the stuff you should have on your list is as follows:
Year
Any reason why you're looking at a very early Testarossa? In my experience, there's not a massive difference in price between early and later Testarossas. Have a look at this page for the updates that took place thoughout production -
http://www.red-headed.com/articles/testarossa_versions.html
Condition
It goes without saying. There are a lot of poor Testarossas out there. Check everything, check everything and check everything again - then get someone professional to do it!! If it's been crashed, has dodgy paint, is missing anything or has non standard bodywork - walk away.
Service history
Must be complete in every way. It's a big complicated engine, and you don't want to even think about the bill to put it right if it goes bang one day - it'll ruin you and your passion for Ferraris. It'll help your resale value when the time comes too.
Originality
Don't buy one that's not the original colour, not the original interior or not running the original engine. If it's running on non standard wheels (as a few are) make sure it comes with the originals. Try to make sure that it has all the original books, wallets, tool kit, etc. Don't worry too much about one that has been converted to dual mirror configuration - most have.
Mileage
Don't buy something very high mileage, unless it's very cheap. Don't buy something very low mileage, unless you want to put it in a museum or your living room. If you want to drive it - something that's been regularly used but not used to the point of high mileage is best. You don't want to pay the premium for a v low mileage car, which will have been sitting for potentially VERY long periods, and will have the capability to put you off Ferraris forever with a string of niggling failures.
Colour
Don't buy a white one. Your mates will think you're a complete idiot, girls will run when they see you, your wife will leave you - and if we ever meet, I'll laugh at you!!!
Finally - if you can't find a Testarossa you like - buy a 348. That's what I did, and I've not regretted it!!! :green:
Have fun too - the search is all part of the fun!!
Bazil