Quoted from Trekkie1978:1 - The ramps are exactly the same...even down to the sticker on them.
The stickers are definitely different, I don't know that the ramp plastic is thinner but after all the cheapening of Stern games over the last few years why is it so hard to believe that they are using thinner ramps?
Sterns games definitely got lighter around Tron/Transformers (at least the Pros), my Tron and SM sat side by side and when you nudged them there was a very noticeable difference in weight and pretty much everyone that played them commented on it. So it wasn't just my imagination.