Welcome aboard! I hate to state the obvious, but it would depend on what products you're talking about. There are some the car is real fussy about like coolant, so if you start substituting generic products you better be damn sure they're the same specs as the ones the book recommends. If you're in warranty you wouldn't want someone to deny a claim based on a Pepboys oil filter they spotted. Figure out what product you want to replace and do a search on the forum for that product, if you still can't find out. Ask a specific question about a specific product. The forum member are glad to help if you've done your due diligence.