If you want top value for money then shop around and remember that it's much better to replace all your parts at once - even if some are still working well enough, rather than trying to update one part at a time! If price is no object then order from the company with the fastest delivery service available... or simply go direct to the manufacturer instead since they often offer special deals on whole-vehicle conversion kits which can save money in the long run when compared with buying individual replacement parts.