do i really need 3" exhaust

I ordered the 3" X pipe from TTI this week, I also bought a set of the smallest muffler I could find. Here is a pic I plan on putting a 90* on the outlet and bringing the pipe out in front of the rear tires.

This is the outlet I plan on using. I expect this will be very loud. I wanted to run a tailpipe but with the springs narrowed I know the 3" wont fit so this is my only real option. I am not a big fan of having the exhaust coming out the side but I am hoping it has a sound similar to the sidepipes on my 72 383 stroked corvette. Any one else ever use these mufflers? I bought them from ebay, they are made by performance Dynamics. they were priced right @ $50 shipped.
Rod