A couple of thoughts:
1) If a restoration, just look at all the Chevy muscle cars
at the B-J auctions. Most, if not all of these cars have
the SMOG equipment. It's the thing to do these days.
2) If you can't go for the entire system at least get the
SMOG manifolds and install them with plugs. You can always
add the SMOG equipment later.
3) Remember, the SMOG pump can be modified to be "free
wheeling" so it doesn't actually operate.
Remember what Fernando ( Billy Crystal ) said on SNL?
It is better to look good - than to be good!
Lastly, the price of these systems and components will only
go up in value in the future. Better to get the system now
if you can stomach the cost.
Steve