I'm not sure of the quality of your intermediate line of LA-Sax since my experience is only with the one I play now. I don't see any reason why it would not be a good intermediate horn. I do think that LA-Sax has a reputation as a "gimmick" sax because of the wild finishes. My horn was their top of the line "Newport" Series until they came out with the "Chicago" series. This horn is very heavy with thick wall metal and heavy duty post on it. I feel that your LA-Sax Tenor and most any horn should play well if it is set-up and regulated well. I think that eventually several saxophones with the Taiwan connection will prove themselves to a higher quality than they are given credit for. Just look at the Cannonball. I just purchased an Antiqua soprano and really like it. That stuffy D sounds like your low C key is too closed even in open position. Play a D2 with your octave key depressed then slowly close the low C key...you'll hear the stuffiness kick in. With your horn jumping octaves so easy, then I sure would have a repair tech that knows the sax regulate it out. Having all your keys adjusted to the proper height has big influence on the intonation also. Unless I was playing in a rock band or big band looking for a cutting power sound, I wouldn't worry about the metal mouthpiece. Just make sure your not playing on the one that came with the horn. In general, I would say that someone could purchase your horn, take it to a reputable repair center to have it set up for optimal playing, and then have a great tenor to play on.