I thought you could get more for them...before you sell...get a clear idea of what road you would take if you had the money for them.
Are you going to take the same money and buy something else? If so, what? What will be "better" than the Theil's for $800ish?
If you combine the sale money with other money you have saved what then? What speaker and then what approach on the rest of your system?
Are you sure you have to have a "tube pre" and are you sure you have to have seperate pre and amp?
Are you sure your budget is only $1000?
I would answer these questions first.
1. budget...how much do you have to work with all together, is there any flexibility and if so how far will you stretch?
2. Do you have to have tube-pre and seperate amp? If not, you probably can find solid state seperates that fit the bill or an integrated that takes you where you want to go. (also, an integrated saves you the cost of a pair of interconnects) Sim Audio Moon I5 ($1200-$1350 used).
3. If you forget the above and decide to sell the speakers, what them? $800? What can you buy that is better for $800? Will you combine other money, if so, it will change the whole dynamics of what you are doing. AN ASIDE: I am not saying these are "better" than the Thiel from a purest stand point, but given your situation here is what I think. If you go to change speakers, look at the PSB Stratus Gold (or Gold "i")...tons of ROCKIN Speaker(does well with finnese also). Goes down to mid thirties (literal chest slamming), plays very loud without losing focus and is reasonably priced. Can get the old Gold (not i version) for $600 to $800 and you can get the latest "i" version for around a $1000 (should be one on AGON now). I owned the old Gold and sold it to a best friend 2 years ago and they still are one of the best values in full range speakers you can buy (he still owns them, still likes them, still likes me). In my house (12x19x8 LR), when cranked, just using a top line receiver at the time, I could literally shake the house and slam you in the chest with the right music. Also, they are VERY VERY easy to match, run about 89db or 90db at 8 ohms so you don't need a lot of power to carnk them. I started out with a little 30 watt receiver (20 plus years old) and then graduated to a flagship Yamaha and then beyond to the "true" high-end stuff (although I am still amazed at how good some of the "cheap" "junk" is...it will often take you 85%-90% of the way). Each change I made they responded well and sounded better. Highly recommended. (since then I have owned Sonus Faber Gauneri (10k), Kharma Ceramique 2 (11.5k, JM Lab Minis (8200)...and have tried many many more, because I am good friends with a dealer, and the PSB can hold their own. I have asked myself many times if it really was worth 10 and 20 times the cost? Very subjective but I was lucky and only paid $500 for my PSB...you do the math, that is a lot of supporting equipment and/or a lot of music.
Let us know what you deicde, I am curious and hope the best for you.
charles