My Mondial is a coupe and my daily driver. Unlike you, I have a need for sound (and looks), my Diablo had to have the Quicksilver, the 348's had to have the Tubi/Hyperflow set-up, and I just put a Level 3 Capristo/Hyperflows on my Testarossa, so as you can see I am not exactly conservative. The way I look at it is if I am going to do an install, I may as well go for the full set-up. I honestly could tolerate even an F1 sound, although I doubt it on a Mondial. Thanks for the advice though.
From past experience with a non-Ferrari I found that removing the cats and keeping the stock muffler gave a sound that was much less tolerable that a performance exhaust with the cats in place. I would be interested to know if there is a major difference in construction on a cat vs. non-cat muffler beside the external tubing to match up with the rest of the system.
I got the 308 back this morning with the Larini and the Hyperflow cats installed. It is louder than the stock system, especially when I get into the throttle. If I cruise at 3500 rpm with the top on and the windows closed it is louder, but does not overpower a conversation. Stepping on the gas picks up the volume to a level I wouldn't want on a long trip, but at a constant rpm it is okay for me. I believe it is a very personal decision as to whether these systems are too loud. Those of you who use your car for an everyday driver might feel that way. As a fun third or fourth car I like the sound. Maybe spending so many years around Top Fuel cars has skewed my feeling on what is loud, or just plain killed some of my hearing, or both. For right now it is fun to have a car that sounds so much better than stock.