Flowtech Glass Packs

I have a 2000 impala ls with the 3.8l v6 and i was wondering if these http://www.autopartswarehouse.com/performance/basket.php?makeid=5&modelid=39&year=2000&partid=25&brandid=1033&page=1 (scroll half way down the page) would fit without hurting the car. And does anyone know what they will sound like?