We have the 5.2 ones, in stock: http://www.ricambiamerica.com/product_info.php?products_id=343560 It's really just a question of which route you prefer. I wouldn't say one is "better" or "worse" necessarily... just a preference on the part of the owner.
Do you rebuild them, or send off to QV? If not QV, are they as good, or better? I like that they are readily available but hopefully I won't have to do this.
They are indeed sent to England for the rebuild, so our turnaround time is usually about 10 days. We're trying to keep 2x sets of the 5.2 and 1x set of the 2.7 on our shelf, but its easier said than done.
Some people prefer to stick with OEM, may or may not eventually have the same issues. Some prefer to go aftermarket which may or may not have their own individual quality issues.
The only thing good about OEM is the heat shielding. And the ones Daniel supplies keeps them. Plus, he provides a 2 year warranty, and I think that is unique in the business. The fabspeeds do look nice, they are a bit more money and I would have them coated by Swain Tech if I were using them. Replacing 355 OEM headers with more OEM headers is like taking colon blow two nights in a row. The same sh#t is going to happen again.
You will not find a better Header then the ones from Fabspeed, Call Jeremy there and tell him Glenn sent you, he'll work out a great price Also Daniel is the man as well but my office and Fabspeed are next door neighbors so I see first hand-- Very nice stuff-- a little pricey but hey its for your Ferrari Good Luck