Service or Replace ARC D90 Amp

I just spoke with ARC, and refurbishing my 1982-vintage ARC SP-8 and D90. The D90 could end up in the $2K range (something like $5-600 for caps, $1000 for tubes (turns out the D90B is cheaper to retube, but I can't change what I own...) plus shipping and labor. (The SP-8 is much more reasonable, and since it has a phono stage, I will definitely keep it.) I've seen several used, newer, ARC amps in the "For Sale" section, with VT100s in the $1700-2000 range (depending on whether MkI or II). So the question for the more experienced is: would you send in the D90, or look for a used, newer, amp to replace it, and sell the D90 "as is" - sounding pretty good, but definitely nearing the point where it will need servicing by someone. (I found another post with the opinion that the D90 is a particularly difficult/dangerous amp for the inexperienced - me - to work on themselves, so that's not an option; I could replace tubes, but replacing caps and biasing are beyond my comfort zone.) Thanks in advance for your thoughts.