Letterbox SD Quality

Today I watched a Sci-Fi Channel mini-series that I had TiVoed. It is of course SD since it is Sci-Fi and they also letterboxed it. I stretched it laterally on the TiVo which was already upconverting to 720p as well. Then I had the projector stretch it vertically to make it look right. At first especially during the credits you could tell how stretched it was. As the show continued the quality really wasn't too bad or as noticeable. There were scenes that looked worse than others. It definitely makes you appreciate HD content even more.