Willie
AV4 component should give you the best result (although some argue only as good as RGB scart - AV1 on Tosh)
If you've got component on your DVD player I would use it.
I've got a Tosh SD210 connected via the standard red/yellow/white cable supplied with the player and it's spot on.
I remember when I set mine up origionally that I had this problem of getting the DSP options. It seems sooo log ago that I can't rememebr exactly but I think it was down to the DVD setup and whether it was outputting PCM or Bitstream.
Found this thread that may (or may not) help
Toshibe 36ZP18P connections to Toshiba DVD SD100EE
Cheers
OG