Tough situation....here's my rationale on this:
1) Viper = 2 seater....great for cruising with that special someone! (remember to keep taking your wife out on dates even though you now have a baby or the romance disappears and no matter what car you have, it won't matter if the romance is gone)
1a) When your son is old enough to want to go for a ride...the Viper is the "Monster" he can brag to his friends actually has a fire breathing dragon powering it....makes for a great story!!
2) Porsche = not as rare as the Viper, yes it does have 4 seats, but are you taking your son and two of his friends out? That's what SUV's are for....
2a) Porsche = can easily be procurred at a later time as a friend to share garage space with your Viper and then you'll have the best of both worlds
3) Viper vs. Porsche in performance, handling, driving fun.... well the Viper demands you pay attention at all times, it is the edge of the envelope in so many ways and that says something about your personality, you as a driver and of course sets you apart from some Porsche owners who simply by being able to buy a Porsche now feel that they are exceptional drivers because the car makes them look that way (with it's active handling/stability systems).
4) Viper vs. Porsche in WOW factor. I don't know about you, but I'm not looking to impress anyone, I'm a car guy and dream of owning about 150 cars (thankfully I got my Viper first and a SL500 so far....just 153 more cars to come) which I know I'll enjoy driving as long as I draw breath. You're married with children, so early 20's girls WOW factor likely isn't much of a concern for you. So it's your family, friends, your co-workers who are affected by the wow factor....and you know them best! At my workplace, I have people approach me all the time who heard from someone, who heard from someone, who heard from another person that I own a Viper and they are so excited to talk cars with me. I know two co-workers with Porsches and neither of them are known as "Car Guys".
4) Viper vs. Porsche as an investment = They make tons of Porsches, I can buy a mid to late 70's Carrera in good running condition any day of the week off ebay for $15000.00, I don't know if Viper prices will ever fall that low compared to their purchase price, so I think because of the Viper's rarity, you'll do better on the Viper. This doesn't even account for the crazy money you can make taking the Viper somewhere else in the world where it might be the only one in that country or continent and driving it until the richest person in that area just HAS to have it.
5) Viper vs. Porsche clubs.....well I don't know the answer to this one, but maybe someone else does who's participated in both events. I can tell you that both my Porsche owner friends/co-workers who drove my Viper had the smile on their face you get when you've either just got laid for the 1st time or you've stolen a bag of diamonds. I asked about their club events and those smiles disappeared instantly.....not a good sign!
Regards,
Aaron