Do you lose enhancements if using TiVo?

Say your HDTV set or tuner has line doubling and the other tricks. You use good old TiVo to record off standard cable). When you play back a TiVo recording through a set with line doubling and pixel doubling and whatever else, do you get the enhanced picture or basic TiVo output?
Tivo is a recorder, it puts out only what you put in, if you can record with line doubling or whatever, thats what you get during play back no options.
I believe that TiVo outputs an interlaced signal which should be then "line doubled" (that is converted to a progressive scan) by your HDTV. The picture quality, however, may not be the same as the original broadcast, even in highest quality recording mode. I looked for the specs on the number of scan lines output by TiVo in the various modes but I could not find any specs on the TiVo website. It seems that they are selling the convinience of the product and not the performance. I did find this review of the performance of the TiVo, although this was done using a satellite feed, not a cable feed: CNET Review
Tivo outputs the same resolution all the time, NTSC 480i. The difference in recording quality from stand alone TiVo boxes is that there are greater compression artifacts like pixelation and macro-blocking when going to a lower quality.

The TiVo that is integrated with DirecTV's service, like the Sony SAT-T60, Philips DSR6000 or Hughes HDVR2 record with absolutely NO LOSS in quality. None of the current units will record anything beyond an NTSC 480i signal, though.

An HDTV Tivo is due to ship later this year, but there is no shipping date yet, nor a price.
The picture you get out of a TiVo is dramatically decreased in quality. Any program you watch through the TiVo (including live TV) is compressed, recorded to the hard drive, decompressed, and then displayed. This is how they allow such features as pausing live TV, rewinding live TV, and being able to record an entier show after you've already watched half of it. If you expect HDTV quality, you will be disappointed. Actaully, if you expect the same quality as what basic cable provides (and have TV larger than 27") you may be disappointed.

This isn't a knock on TiVo...I own one and I don't believe my wife will ever be without one. It truly is one of those products that once you get it and "get it", you'll never want to be without it. Does *that* make sense?
Nrenter, while what you say is true for stand alone TiVo boxes, it is incorrect for the integrated TiVo boxes like the Sony SAT-T60, the Hughes HDVR2 and the Philips DSR6000, which record with NO LOSS of picture quality whatsoever and are able to record dolby digital as well. The newer HDTV TiVo units will be the same way, with ZERO loss of picture quality, as they are recording the exact stream that is being sent in the first place.

Stand alone units have to take the analog signal being sent to them and run them through an A/D converison and compression, then do a D/A conversion when it is output. If you want TiVo, and anybody who has ever used one for any appreciable length of time does, then go with the best one there is - the integrated DirecTV units mentioned above. In addition to being better, they are substantially cheaper.