"I like everything I read about the Benz (lowest $1800) and after reading about the Transfiguration cartridges (lowest $2450) I was very impressed. That being said, I am very concerned that with the VPI Prime I may be spending more on a cartridge than I should considering my TT. Please honest opinions, you will not hurt my feelings.Opinions help you learn."
Reading and listening are 2 completely different things. Carts that you read about will probably sound different in your system (how much can vary).
Synergy is much more important than price.
Your TT is fine. I wouldn't make plans to upgrade before you listen to it.
Keep it simple. A LOMC is fine. Match it to a phono pre that can handle the output and don't worry about an SUT. Also, at this level, I wouldn't fool with tubes either.