I'm like you, haven't ridden for over 20 years and bought a C90T. My friend bought a new Harley Softail and immediately changed the pipes for louder ones. I found a site online that's
BoulevardSuzuki.com, Suzuki parts & Suzuki accessories, The #1 Suzuki Motorcycle Parts and Accessories Shop, and they have all kinds of different pipes. Quite honestly, I gave up when I saw all the different pipes, because I'm concerned about screwing up my new bike by putting on the wrong thing. Have you thought about asking your dealer what you could safely put on your bike? I know mine is really helpful in that area.
I have one more thought. If you look closely at your pipes, where the pipes go into the muffler and come out are very close. I thought about having someone weld in a piece of pipe bypassing the muffler. But, as small as those pipes are, I'm afraid it might sound like a baby fart in the bathtub! Just a thought.