Quoted:
A rifle that old, of that model, and in that kind of shape, I'd just leave it alone. If you want a tacticool rifle, get a beater and rebuild it.
It's your rifle, and you'll do with it what you will, but that's my .02 worth.
+1
i just bought a 1978 DSP in similar condition to what you describe. it cost about three times what your budget is for upgrading.
no way in hell i'd tear it apart and pimp it out with the tactical crap. do that on a modern gun.
if you want a nice "tactical" gun, spend $150 for a used gun, get a Christie & Christie's "Super Stock" (which costs more than your budget) from www.1022central.com and then upgrade the trigger, get a new barrel and whatever else you desire.
ballpark price for a nice 10/22 based "TactiCool" gun will be about $600 by the time you're done
a new Deluxe Sporter (DSP) ain't as nice as your old one (has the new, MIM bolt, polymer trigger group, engraving all over the barrel, etc.), and if you lose any of the old parts, or chew up the old receiver when it's in "tactical" mode the value won't be what it is now.
they ain't making any "new" old stuff.
of the old DSP needs work, i'd get a trigger job done that cleans up the stock parts. on a new gun, i'd replace parts in the trigger group, or the whole trigger group, replace the barrel, replace the stock... in short, change out everything except the receiver.