Exhaust mods on n/a cars

[Dwight Varnes <mxbreed@lancnews.infi.net>]

Since the center muffler on my car has elected to split, it's time to
make that exhaust system I've always wanted. I thought maybe some of the
engineering types out there may be able to comment on the strangulation
occuring normally in my car.
Obviously, I'd like to optimize performance, but still retain some
semblence of a muffler so that my passenger can hear me. What I proposed
to do is replace the system behind the converter with a 2 or 2 1/4"
system, one muffler, and maybe a glasspack to help calm the 'boom'. Some
have suggested I go to a larger cat, as the cat is fairly restrictive.
This would mean additional fabrication and expense, that I am doubting
will gain me any rel benefit. The euro headpipe is the same size as the
inlet to the cat, so how is enlarging the cat significantly going to
improve flow? As I am removing other obstructions downstream (one less
muffler, freer flowing) I'm probably going to get as much as I'm likely
to out of this construction.
In other words, the narrowest point of any system will dictate the flow,
so if that part is the headpipe, of what consequence will the converter
or what follows have on the rest of the stream?
-- 
"Life is too short to drive boring cars."

Dwight Varnes, insurance appraiser and car nut
1970 124 Spider (restored, mostly)
1986 Audi Coupe GT (bigger engine at machine shop)
1989 VW Jetta GLI 16v (the wife's ride, needs restored)
1984 Nissan 4x4 Pickup (rust never sleeps)
1965 Buick Skylark conv. (more fun than you'd think)