My tenor doesnt got a high F#. is there such thing as getting one "installed"? Cuz i really love my horn, and dont want to buy a brand new one.

My old (alto) sax didn't have one, but I was still able to play high F# (though I had a bit of trouble at first). My new sax has the high F# key on it, and it is much easier to play F# with the key. You should consult someone at your local instument-repair place to see what is the cheapest and best meathod.

Because of the volume of the key chimney, a saxophone needs to be designed either with or without the F# key. You will end up with poor intonation if you add one. Many professionals special order their saxophones without high F# because they feel the disruption in the bore that high up the sax affects the tone. Joe Lovano, for example, plays a modern Borgani without an F#. Yamaha makes their Custom Z in both varieties. I have tenors of both type, and I don't think that's the dominant difference.

Thanks everyone for your help! Im going to keep my tenor the way it is and later get one w/ high F#. Its really interesting all the things just one key can do to the instrument.