Its all about being comfortable. Myself I like the m11x. Its what fits me. A friend has the same b4.1 I do but uses a Futaba radio. When I drive his car I cant make a clean lap.
Most all radios now days are very nice and not using AM ect.
Will the difference in radio performance make you better. I doubt it. Will finding the radio that fits you make you more comfortable allow you to focus on your driving more. Probably. Be it a $100 radio or $400 one.