Looking to upgrade my preamp, suggestions?

I think you already have a very fine preamp.

Another vote for ModWright. I've had the SWL9.0SE for many years with all the upgrades. 

I am presently using an Audio Research LS27 which I got for $4000.  But I previously had an LS26, which should be going for around $3000.  You can not do better for the money.  Plus are both single ended plus ballanced.

The C48 is probably as close as you'll get to a tube sound with an SS pre. I have no doubt you'll be pleased. Let us know...

I use a premium streaming service DEEZER, 16/48 and vinyl but most of my content is from DEEZER. I listen to old and new hard and prog rock. My system also consists of a older class D Rotel amplifier and B&W 600 series towers. My goal was to upgraded some components to take the edge off at higher volumes and add tube qualities to the sound. I added a Wadia 321 DAC and upgraded my preamp to a Rogue Audio RP-1. I am pretty satisfied with the results. I like the Tube/ Class D combination at this point. Maybe go full tube someday. Rogue also makes an RP-5 that comes in at about $3,500, it’s the next step up in the line from the RP-1. I like the people at Rogue. They answer the phone if you call them and gladly talk about the product. The only thing I don’t like is the remote does not turn on the unit and it does not work with my Furman on/off switch. There are lots of youtube vids about their stuff and reviews out there. Here is the chief designer Mark Obrien talking at Wilson Audio. https://www.youtube.com/watch?v=-lSaMkzqTiA. PS Audio just came out with a new DAC/Preamp combo for $1,500 and I think they have or had a trial program going (solid state option). http://www.psaudio.com/products/stellar-gain-cell-dac/. I have never had any of their equipment other than power cords but their shop is just down the street from my house and they are really nice folks as well and when I called them to talk about the products they invited me down for a tour which I thought was cool.