For ME, I look at aftermarket parts as a potential risk for substituting quality. Now let me also say that there are a number of aftermarket parts manufacturers that can and do produce quality replacement parts. They may be equal in quality and may in fact be even produced by the OE supplier for GM but possibly licensed to be sold under a different brand but we the consumer would NEVER know about it.How important are OEM parts? Under warranty and afterwards? Pros and cons? I get the basics but if I use aftermarket parts how can it be negative in the long run? Novice
So you'll have to ask yourself this question - how important is the mechanical health of your vehicle to you and do you plan to keep the vehicle for a long time?
For ME personally, the answers are YES and YES. In all of my previously owned newly purchased vehicles I have always gone for the cheaper discount auto parts store replacement parts. And while these parts did their job some may have failed prematurely while others faired well but may have not lived as long as the original OEM part. Also, and this may sound odd, but for me it also changed the character and feel of the vehicle when adding foreign parts. It just didn't feel original to me. Didn't feel like stock. Almost as if the car is out of balance. For this reason I have vowed to use only OEM parts for both of my current newer vehicles. This includes ALL fluids, mechanical and electrical parts. Well actually the engine oil I pick up at Walmart and is the Pennzoil variant.
Thankfully this has served me well and 5 years later with almost 101K on the odometer I have had no major issues to report (*knocks on wood). All parts are replaced as instructed in accordance to the owners manual via the Maintenance Guide. And to this day my vehicle runs wonderfully.
I should also point out that OE parts are not always perfect and some will fail prematurely. However I still feel confident using only original parts.