Reflection is pretty hard to do sometimes but not if you know the right technique! Here's the simple way to get it done.
Download the source image here.
Create new document and make a gradient on the background just like above.
Cutout the car image and place it on the document.
Duplicate the car image and flip vertically (see above sample)
Using the Polygonal Lasso Tool, cut out the tyre parts like above.
Paste it in between the car photo. Now go to Edit> Transform> Skew. Adjust the tyres so that it touches the main car image.
Do the same for the back part of the car.
Once you've done that, merger the layers (Press Shift button and click on the layers and then press Control - E)
Erase the reflection part of the car using the Eraser tool or mask it if you want. Set the Fill opacity to 50%.
Make a layer above the reflection. Select the Rectangle Tool and make a box just like above.
Now go to Edit> Transform> Distort and adjust the rectangle.
After you've done that, go to Filter> Blur> Gaussian Blur. On the popup set the slider to 3.5 and you're DONE!
Download the PSD file here : http://www.ramesstudio.com/adobetuts/reflection_sample.psd
This same technique can be applied to full portraits, product shots etc. Do give it a try ya!