There is no requirement (in the USA at least) that your VLOC radio have any certification for IFR. Just like your altimeter, attitude, CDI, engine, and landing gear, it's up to the builder to determine if it is appropriate for the kinds of flight the aircraft will do. The VAL radios which are becoming popular carry no certifications.
The only two items that require "meeting the requirements of the TSO" are the GPS in IFR and the transponder always. Technically, these don't need to be TSO'd, but proving you meet a 800 page TSO without actually getting the TSO at the end and increasing your sales volume 10X is a bit silly.