Good modeling work.A few suggestions you could try...I think the paint should be shinny with reflections or a reflection map [ try raytrace ].Maybe use meshsmooth to smooth out the tank a bit more.Also the back wall looks washed out with light.Maybe try excluding it from a few of your lights or just use diffuse lighting with no specular highlights.Maybe a dark omi behind the bike for backlight to break up the shadows abit or use less of a shadow mutiplyer.Still a good image.

I used a raytrace material.I used meshsommth but it fatterns the model but i wanted sharp edges.I used radiosity for fast rendering but as u can see it doesnot give me a good result.