Does using an expensive oil make a difference ?

i run Royal Purple and have never looked back. My engin seemed to run smoother and slightly more powerfully when I switched to synthetic.

I have heard a few SN95 owners saying that they never felt the difference, but i am under the impression that it is due to the heavier car. Basically I have heard that until you get considerable more power,you wont feel it. But I dont know, Ive never even driven an SN95.