How far is Erie Pennsylvania from you? J3 Competition might be able to help. I know they sell Tillett Seats and they might be able to help. They also might know of a few kart shops in your area.
They are really are a great group of guys and I highly recommend them for anything. Ask for John or Jim if you decide to call. Justin is the main tech guy but he usually deals with the racing side of the business.
Otherwise Comet is also a very good place to go get setup but J3 Competition might be closer to you and like it said they probably know someone in your area that you can go to.
the other thing you can check out is Kart Directory online. It’s a new website that list hundreds of karting Related businesses with phone number and contact information. I would also check that out