hi there...
well i find the render really good and the reflection is coming very reasonable but i think thrs some problem with the samples under the car and somewhr near to it...it can be a problem of inadequate lighting or you can increase number of samples or play with filter.....it wont take much time in reder if u will only tweak the samples...

anyways it was a nice job to see...
thanx for it

regards
bhumit