The Gaming Liberty has the most comprehensive interview with the musicians behind those GTA radio stations, I think I could ever imagine seeing. From the article:
“Over the past few months I’ve had the great pleasure in interviewing four key players behind the music of Grand Theft Auto- Colin Anderson, Grant Middleton, Stuart Ross and Paul Mackie. If you’re like me the original GTA, and especially its soundtrack, meant a great deal to you.”
My time at DMA only intersected GTA up until mid 1997, during which I was on other projects such as Body Harvest, but I certainly had fun on the bits I did have a hand in. (Mainly writing dialogue, which would never ultimately be used after I left.) So I’m learning more here about GTA, than I ever knew at the time!