XYZ and many of these other brands are import kits of the cheaper variety hence the low price big size kit options. The things we see with import kits is the fact that replacement parts are often hard to get and they are not compatible with local DBA or even AP Racing parts. Flex, leaking and distortion also come up quiet often when people contact us to repair these products. Buyer beware and also remember that it is harder to certify these kind of kits so make sure you check with an engineer and insurance company if you want them certified.