Yeah, the Cool Fire car looked familiar. There are decal kits to replicate many teams that raced in the STW, but were not produced by minichamps. I think the time period is generally after the STW became a largely indepdendent series after most of the Works teams pulled out.
That is quite an impressive model, I've converted 2 cars, but they were obviously a very crude job compared to yours. A Macau/Biela Audi A4 and a Macau Juicy Fruit BMW E30.