Nice website it has a clean layout and a smooth straightforward interface. The Challenge Boston and Boston tees are the strongest graphic wise. I like your logo and think you should incorporate that into more of your shirt products. I'm not a fan of using the other team logos because its not very creative...i get the sense "well I could've done that myself." Instead try using the familiar parts of the logo like the font, and applying it to a unique design with the same color way. Also not every piece needs to have your slogan or company name on it. Sometimes just a graphic is nice. Just my opinion.
But hey keep doing your thing! Hope this helps.