Sorry, but no. Supporting multiple .exe's is a lot of work, and I would rather spend my time on new features and fixes. I do understand that most people use non-Steam version, but there are multiple technical reasons why I chose and developing for the Steam GTR2.exe. For the record, another important thing about my work is that my focus is offline racing, so if anything works online, it is just by luck. Graphical Enhancements, for example, do not work online for sure. Also, there's no enforcement for online - so if you enable flat spots/dirt pickup but your opponents don't, you will be at a disadvantage.

In case you are not aware - you do not need Steam to run Steam GTR2.exe (I do not like Steam either). But in order to use my plugin the .exe must be the latest GTR2 .exe available, which is Steam GTR2.exe.