Not real sure who made either ones,but the cylinders are around $50+ new &shipping and the shoes are about the same price.The big cylinders and shoes together will allow you to hold the car back while building boost on the starting line.
Stock ls1 seal have a spring base/locator built into them,aftermarket ls1 seals for dual springs press onto the guide and no locator. dimensions are .500 guide with 8mm stem hole.patriot # is 8414. don't buy comp seals