Oh, I don't have any regrets..
I love my 9-3 and I'm glad I bought the one I did.
But this is twice something like that happened. In late 99 I bought a new 2000 Legacy GT Wagon. 165 naturally aspirated horses. A year(or 2) later Subaru came out with the H-6 and a turbo available in the Legacy.
Right after I bought the car I got a customer survey in the mail. In the comments section I said: "Subaru really needs an H6 or a turbo four to compete with the Accord, Camry, etc. While the Legacy is a fine car, without a bump in power, it will never compete with the main players in the midsize sedan market."
I guess they listened.