Like George,(I can see him cringing at the thought,LOL) I too have owned a few Porsche 356's. I have found my Vintage replica to be a more than satisfactory substitute, mechanically sound, detailed reasonably similar, etc!
I bought mine used, it's a 69VW pan ( I thought it was a '64 until I re-registered the other day)and it was built I think in 1999 or 2000.
It had the single carb 1776 and disc brakes up front. It only had 2500 KM's (?) on it and I paid $17,500.00
If you watch eBay you will see some resellers asking $19K-25K
Individuals selling their cars seem to ask $10-15K
There was an older InterMcManiac, yellow, on eBay and I think this guy went over the top with Porsche-like features and he was touting a price in the $13's based on eMail exchanges...
Think about how much you plan to use it and what type of driving you do, and where. Your wallet will be your guide.
While a lot of guys on the forum talk mechanical stuff, don't overlook the accessory details, they cost a little money and are options, but they really are worth it to sell the look and finish off your baby!
Definitely get a bigger engine no matter where you turn your key!
Don't forget to look through the files section...A lot of nice pics of various cars, classic, widebody, etc!