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.
Sell it. It is not worth $2K in upgrades.
I would do this if I were in your place, before making any hasty decision about this amp. I would seek out an outside source someone competent who knows the amp or at least work's extensively on tube gear and let them give you an estimate on the work. Most of your cost is going to be labor and shipping, such a heavy amp. So if your can cut just the shipping out and ARs high labor cost you might find out it is more economical then you thought. And a grand for tubes sounds excessive I am sure someone on the Gon can steer you in the right direction with that.
If you can use the amp as is for a time.. I would skip the referb, and use the referb money to buy a newer ARC amp. Save the old amp once you get the new one.. (you may decide at a later date to :sell, fix locally, or have ARC do it)
After many years of being an audio challenged person (audio nut) I have discovered it is best to KEEP stuff you like, even if you cannot use it.. because later, you will WISH you had kept it!
A few years from now you may be glad you kept that lump in the closet, and are overjoyed to have it back. (after getting it fixed.)
You might want to consider having it upgraded by someone other than ARC. If you are interested in just inquiring, Great Northern Sound Co. is a reputable company and can perform such upgrades, maybe for less money. Worth looking into!!
I agree with Elizabeth. More than once have I had the desire to repurchase equipment I previously owned and liked.
Agreed with Liz and Cyclonicman. I have had several ARC gear modded by Steve Huntley at GNSC over the years to stunning sonic results. (Classic 120 mono's LS16MKI, PH3SE, REF2 MKI, REF Phono). His mods go much deeper that what ARC can ever provide.
Talk to Steve for advise. He is a wealth of knowledge on ARC and Wadia stuff.
Good luck.