Tvad is correct, it is indeed a classic and may someday increase in value. If you choose to hold equipment for that end, this is a great piece.
I modified my SCD-1 years ago and have not yet felt I am lacking anything in Redbook to any player I have heard. I would consider the mod's too in your list of choices.
For me it remains the best money spent on my system and should keep you current for a long time to come. Eventually we will see newer better technology that is worth the money, but this remains a top shelf unit, stock and even better modified.
jd