Audio Research LS series......

I am thinking about adding a tube preamp to my system. I use a highly modified Accuphase C200 right now and I am happy with it. I would like to have a tube preamp that I can mod...so the top price would be about $1500 used. I was thinking about changing the coupling caps with some V-caps(or other). My goal is to have a very natural,transparent sound,and a very good soundstage...the pre would be warmer but not tubey..to compliment my SS C200 preamp. I have read reveiws on the LS2,LS15,& the LS17...any thoughts. I use RCA connections and need 2 sets of outputs. My equipment is...

VAC 140's
NBS cables
custom dynaudio speakers

Thanks for any input...

P.S. I know there are many tube pre's that I could use...but I think that for the money I want to spend the ARC would be a good choice.