I have the same problems.
A french guy i work with used to work for renault, so i asked him if he knew. he ended up asking a guy still at renault.
Items to consider:
the 182 doesnt have this problem due to a re routing of the exhaust, adds 10mm clearance to stop the exuast hitting the chassis under engine rocking.
It sounds like yours has got worse/you have recently got the car and instantly notice the issue.
I would suggest not just to renew your engine mounts but to use some upgraded ones that are quoted to illiminate the vibration issues.
I hope I dont infringe any rules by saying i think i spotted some(as i want these too) on the K-Tec Racing website, they come as a kit i think. Im sure you could look around for alternatives to even out the playing field
I have had my car for 4 months and i think it has got worse and hope to make this mod soon. You may also find some kind of exhaust spacer may reduce the problem too.
You really need to find any evidence on the exhaust/chassis to be sure this is the problem. but if you dont find the marks then the engine mouts may be a cheap 'fingers crossed' option.
hope this information gives you some ideas
Ben