Hinksy
Ben.
Well, one thing is sure--you're already a winner if you've attempted to step beyond your normal "comfort zone" and learned some new things on this build.
The good, in my humble opinion--your wheels look pretty good, although I'd like to see more definition in the "tire" part as far as the black color. The muffler looks really nice too. The general look is pretty well done as far as looking "nasty".
Now for some criticism. I don't know why, but your dunklegelb and your camo colors seem awfully dark. I suspect that that is a by-product of you putting a completely-unnecessary gloss coat on it? Gloss darkens color--sometimes drastically, and you can see a noticeable difference between your tool box--which has a more correct hue of DY on it--and the camo.
Glossing an entire model for one little decal is completely unnecessary. Additionally, if you're using Tamiya paint, you don't need it to "protect" the paint. Also, I know you said you did it for the washes, but I would suggest that you discard this notion. As I stated, you don't need it to protect the paint, and when Shep Paine recommended it in his old, venerable modeling manuals, that was in a day when weathering was basically confined to washes and drybrushing. The gloss finish will basically "shed" the wash off of the base coat and cause it to accumulate in the creases of the model, and not really affect the body of the model--not what you want AT ALL if you're trying to do the oil dot technique, or even add filters. They should be done over FLAT finishes, as you need to have some kind of "tooth" on the finish to grab the tinting color.
I would strongly suggest that you throw that rattle can gloss back in the bin, or save it for when you build your first car model! 
I really think you'll get a much better tone to your colors without it.
The silver that you used for the chipping is too bright, and you have rather over-applied it where it is unlikely to have worn in such extreme manner. Go V-E-R-Y sparingly with any silver coloring on armor models--use a metallic gray for chips and scrapes, and bright silver ONLY for very recent scrapes, or areas of high polish--like track faces. You can still tone that down, along the tops of the schurzen and hull lines.
Hope I don't bring you down about your model. I just want to give you honest critique and urge you to keep working toward improvement. 