Re: What difference does a sax neck make?
A sax neck can make a huge difference in tone, response, back-pressure, etc. and many players experiment . . . many players also stick to the stock neck. In today's day and age, a lot of manufacturers are offering a variety of neck options which opens up a whole can of worms for the many "gear-heads" out there (myself included) . . .
That being said, at your age, I wouldn't worry about experimenting with necks . . . develop competent fundamentals on your current setup. If you eventually decide to go pro, that's the time to worry about that specific of a parameter . . .
One final note . . . although I am a self-proclaimed "gear-head," I use all stock necks, HOWEVER, I have silver-plated the stock necks on my YSS-675 soprano and my YAS-62 alto and as a result, the horn responds much faster, and the sound is much more vibrant than before the plating (My Mark VI alto, tenor, and bari remain untouched, although the lacquer has been stripped from my tenor. I also have a Couf Superba which is also untouched).