Video corrections with TMPGEnc

I am just wondering if the video corrections are worth the extra time to encode when using TMPGEnc.

I record from a PVR150 so I like to use the noise reduction because it helps. However, should I use options like deinterlace, and color corrections when going to dvd format? Using noise reduction usually takes the encode time from 1.5 hours to close to 3 hours. My main question is should I use deinterlace when converting? However I would also like input on the other aspects that I can use to help improve the picture from a TV source, especially one that was recorded using a TV tuner card.

If it makes any differnce I will lise my specs.

Opty 165
6600GT
2gig ram
Hauppuage PVR-150
TMPGEnc Express 3.0