Ryan, where have you seen a $200 group IV oil?
Redline and Motul are both Group V oils if they are what you are referencing.
As I said, it is more what you are comfortable with, but regardless of 5000, 7500 or 10000km changes, a good quality oil should used.
I'm not saying only use 300v or Redline or Sougi or whatever, but poor performing oils are just that.
By all means, try some different oils with the same filter... you should be able to "feel" the difference.
Oh, I knew nothing about oils (or in general lol) prior to owning my M35... but damn do I do a lot of reading!