Im sure there is... I'd go to a bookstore and look for a magazine called "sport compact car". You'll see parts advertised mostly for Honda and Mitsubishi, but there will be some American-made in there as well. Browse around the ads until you see some that look like they cater to the Sunfire or have pictures in the ads. Either memorize the addresses or buy the magazine and start shopping online. If NOPI has your parts, they are trustworthy for delivery.

"Smoother" may be hard to come by. Actually, stiffer shocks might help more - they'd control the springs better and causes less bouncing. However the initial impact may be a bit more rough. It's a trade-off...

Look for something adjustable, that's the key. Set them stiff, soft, or anywhere in between and see what you like.

Also, I don't know any right off, but I promise that there are owners forums for the car. Perhaps do a google search for "sunfire owners group" or something similar. You'll probably find a good bulletin board where the subject has been discussed.