[Collins] Whats a 30K-4 worth?

[W2HX]

Hello folks, I have a line on a 30K-4. It is owner says it is operational on 160 and 40.  It is not restored but it isn't abused. It comes with a 310 (letter suffix not known at the moment) but again, the whole thing is operational.  I was told that the exciter has had some modifcation to get it on 160.  My interest is 80 and 40, not 160.  The only other thing I know about it is it has had its "hard to find" modulator tubes replaced with a "more common" type tube that required only simple modification. The seller could not recall the details, but something about the 75TH maybe replaced with 100th?.

Best part is, seller is local to me (10 miles?). I trust the seller and his description of its operating condition. I plan to visit him in the next few days to see it in person.

Anyway, I am interested to know fair prices for such a set up. 

Thanks in advance
73 Eugene W2HX