First off, you will not likely find a Synergy IIi for anywhere near $3000. And you're right, Synergy preamps don't come on the used market much, but if you're going for the model 8 you might buy something to hold you over until one comes along. In a solid state preamp you might consider a Pass Aleph P. It is perhaps a bit different in its sonic signature, but it is in the same class and can be had for $1700 to $1800 with remote. Many more of the Pass units were sold so you'll have a much better chance of getting one in a short time period. Who knows, you may find it is all you need. It does not have Synergy cosmetics (what does), but you pay for those and the Pass is built like a tank. You may also like to consider a tube pre of which there are several excellent choices. Of course your choices are more limited if you want balanced outputs in which case you might consider BAT.
Which preamp for Rowland 8Ti?
In going to buy a used 8 TiHc. The obvious pre to use would be Synergy II or IIi but they are hard to find used. Should I wait for a used one or is there another pre that is equally good or even better at max 3K?