HEK

So when I bought my Z 3500 miles ago the dealer offered me $19 oil changes for the life of the car at 5k intervals, I asked about synthetic and they told me would cost almost $75. So I'm getting ready for my 1st oil change and since the regular oils now are a lot better than back in the day I wonder if I should go ahead and do the $19 vs doing it myself with synthetic ...I know this topic has been beaten to death but I wonder if going their route is just as well since i wonder what has happened to all my previous rides that I took so much care in putting the best fluids.....i know some ppl even run regular gas ...opinions please .just opinions