is a good place to start. I think they are one of the distributors for the United States. You're in NC, right? Go Tigers!
Clicking through some links you'll find information on Tubi but my best guess would be to speak to your nearest Ferrari brain, be it independent or dealer. Just about any exotic car shop can get a hold of these things for you.
Might want to contact Jason Williams of Vantage Performance too. http://www.vantageperformance.com/ Tell him Taek sent you! I think he has some sort of program set up where you get really good prices.
What I have personally heard is that the best exhaust systems for bling bling value have to be the Tubis, but the best for outright performance are the Ansa exhausts. Ansa makes the OEM systems so their aftermarket ones are a definitive performance increase. They've made OEM exhaust systems for Ferrari, Lamborghini, and even DeTomaso (I'm pretty sure). For 360s the stock exhaust is tough to beat. With the thing opening up at 3,500 rpm the only distinct advantage you might get is in weight savings.
Which car are you going to get it for? I've heard great stuff about Cargraphics and have heard the system first hand. The main complaint about Tubis I've heard is that they are too loud. I heard the loudest version on a 550 Maranello and it literally shakes everything around it! Leave a cup of water behind it and you'll see little waves (Jurassic Park style!) form while the engine is idling.
not yet JRV, am waiting for tools that i ordered ( couldn't buy them at any store in this small town) and then the new plugs, and then I will know for sure to send the FD to be rebuilt by the same guy again...but I might as well be thinking Tubis if they make them for Boxers...I am thoroughly enjoying the 550 as it is an awesome automobile.