True, Offy 2x1 or 3x1 will bolt to original exhaust, no problem. But to mate it up to the Fenton exhaust you do have to do some grinding. Some do a little grinding on both the intake and the Fentons to get it to fit. Some have ground too far on the intake and ended up with a hole in it. (not good).
Myself, I think the split exhaust that is offered by "Kansas Kustoms", http://www.kansaskustoms.net/
is a much better setup with the Offy intakes. You get to retain the exhaust heat for the intake and you still get the performance and cool sound.
As far as intakes go I too believe McGurk is still king. They have a divider inside that is suspose to help with fuel distribution and they (the 2x1),have been reproduced by "Wayne Co. http://www.waynemfgco.com/mcgurk.html, a little pricey but I feel it is worth it.(if you could get one) ***CAUTION***, if you order one from wayne co. have it sent COD because he is having some kind of trouble with people sending in money and never getting their orders. (I for one).
I would like to see the "Fenton" intakes reproduced. I think a lot of people would like to benifit from another choice. And I am sorry "ViejitosCC" but you sound just a little selfish in wanting other people not to have something that you may have. I understand that it is cool to have a setup that other may not have, but it is un-cool to hope that they are never able to match your setup. (sorry)
I say long live the Offy's, and bring on the Fenton's and lets hope that the McGurk intakes will someday be free to sell. Good luck "djed50"

Ed