Hi Kent
I had no problems getting my Birkin Clubman thru Regency with the exhaust exiting the left hand side pipe......I had to make up a heat shield to stop dumb@rses burning their legs (which accidently fell off as I turned onto South Road !!
Noise may be more of an issue with the Cobra............the local Birkin dealer who put my car thru Regency for me wacked a heap of baffles inside the muffler to get it passed .....[and they fell off after as well...........
Good luck
Eldo