Glad to learn some aspect of law is "very simple". I agree its not about Porsche and/or their lawyers making money, it is about trademark/tradename protection, and their lawyers aren't doing their jobs if they aren't diligent about pursuing infringements. But I don't think any of us - Porsche, their lawyers, replica makers (as long as they aren't putting on those badges), replica owners - need lose any sleep over this. If replica builder A begins putting Porsche badges on all their Speedster replicas, Porsche doesn't lose their trademark rights if they don't file suit the next day. If Porsche had knowledge of A's infringement but let it go unchallenged for years before bringing suit - thats different, A has a possible defense. If A put Porsche badges on one car this year, 5 cars next year, 10 cars the year after, and so on, I believe Porsche could prevail in legal action on the doctrine of progressive encroachment - even though they didn't immediately jump on it.
I think I'm breaking trademark law with my Porsche badges being attached to my replica, I also break the law every day by going 5 or 10 mph over the speed limit. I would be more concerned if the car was titled as a Porsche, which it is not. Back to Vince's question; I would be just as proud to have VINTAGE name on mine. From 50 ft away it would still fool some people.