My heart goes out to the Plus/4 but a Basic upgrade for the C64 would have been a better computer. The Plus/4 has Basic 3.5 and the C128 had the 7.0 Basic.
I have the Super Expander on Vice X64 and maybe Simons Basic. I hear that Simons has more memory.
how does Jiffy Dos compare. I guess is gives the C64 better Algorithms for faster disk access ,etc.
Later.
edit
thanks for the links