Question about oem vs after market parts

So my 2012 jetta tdi wagen got a jack shoved through the skid guard into the radiator and now I have to replace the condenser, radiator and core support on it. The dealership wants over 2 grand to fix these 3 things but my local mechanic only wants 1000. I wanted to know if I use my local mechanic (who might not use actual oem parts but others that fit and work instead which I know they do to save money ) will my car still work with those parts instead of the dealerships. I feel like the dealership wants to much money for something thats not that insane of a job to do but I don't want to break down later on and have to replace these parts or deal with another issue from this again.