I'm not sure if this is related to the well-documented "clicking" noise, but when I accelerate hard past 5000 rpm in first gear (and 6000rpm in 2nd) there's a loud and noticeable sound coming from the rear. It sounds like metal scraping. Has anyone ever encountered this? It doesn't seem to affect the performance of the car in any other way. *note: the clicking noise from a stop only occured a few times last year and hasn't occured since.

BTW the car is an 05 coupe 6MT

Thanks in advance