"Interested in 356 speedster with Subaru engine. Can you direct me (to) some (pl)aces to purchase new or used. I'm located in NY"
Well, one comes up on here now and then, but more of them seem to appear on the eBay or BaT (Bring a Trailer) websites. You should also do a search on here for who the better builders are. Buying from Vintage Motor Cars in California, Special Edition (Beck) in Indiana or Intermeccanica in Vancouver are all sure bets. All of them sell new, and often broker used cars for clients. The only place closer would be @Alan Merklin from West Virginia on here, but he's trying to retire and get out of the car building biz. PLEASE DO NOT EVEN CONSIDER BUYING A CAR FROM SPECIALTY AUTO-SPORTS IN TENNESSEE. THEY WILL TAKE YOUR MONEY BUT YOU WILL NEVER SEE A CAR IN YOUR LIFETIME.
"With the significance price difference between Subi and VW engines, what are your thoughts on air cooled VW engines. Which one HP displacement reliability wise would you recommend if at all."
My belief is that the big difference in perceived reliability between air cooled and Subaru is that the Subaru engine has electronic fuel injection, versus carburetors on the aircooled engine. Cars in the USA haven't had carburetors since the early 1980s so fewer and fewer people know how to live with them and even fewer people know how to maintain them properly. Fuel injection just seems to work (until the ECU dies) and don't need any periodic maintenance which appeals to the non-mechanical folks. Beyond that, 99% of us on here will not own their cars, aircooled or Subaru powered, long enough to "wear them out" or for them to become unreliable, so that's really a non-issue. All of the air cooled engines seem to be reliable from 1,776cc up to 2,332cc depending on who built and the quality of parts used, with a sweet spot around 2,110ccs
I would strongly suggest that you spend a few nights using the search function on here (little spy glass in the function bar at the top of the page) to see what discussions have already taken place on these topics (there have been many). It really helps to get as much info as you can.