ST-2 + MD-205 vs MD6-FM

Acquired a Sansui 9900 that had been modded about 6 weeks ago. Problems with reception were fixed by putting up a Magnum Dynalab ST-2. Still having some difficulty getting a few stations I wanted, so ordered and have received the MD-6 YAGI. In the meantime, I put an MD-205 Signal Sleuth back into my system on the Sansui, and now I get the stations I wanted.

SO, the question is - Do I go thru the drain bramage of putting up the MD-6 at this point (customizing mounting brackets, etc), or just leave things as they are? All of the stations I listen to are west of me. How much of a difference in sound quality will the MD-6 afford over the ST-2? I'm not trying to pull any MORE stations, just possibly improve the quality of the signal. I'm also NOT interested in a rotator, etc., or some other brands of the same thing.
Thanks for your assistance.
The ST-2 sucks. I had one and a simple crossed dipole from Radio shack thoroughly beat it. (it was $14.95) Your yagi will work wonders, especially since all your stations are in one directon. You won't need a rotor.