Vibration while driving a hill around 1500rpm (ish) ? Normal or...

[waxxonMTL]

Hey folks!

I had this vibration going on for quite a bit and would like to know if it's normal or I should be putting energy and $$ on trying to fix it..

Problem ; loud rumble when driving around 1500 rpm (ish) ; Ex: M4 at 35km/h try to accelerate and it will rumble.. it's even more noticeable when your going up a hill. For exemple, at 80km/h in M7. then you get to 100km/h and you it goes away..

Possible problem ;

- Awe DP/exhaust loose bolt or something knocking/making a vibration ( but why would it do it only under 1500rpm ish..? should do it at any range IMO)
- Loose heat shield passenger side. Some reported that the wind catch up and make it rattle even more. That could make sens as I believe the sound is louder at 80km/h then 40km/h.
- Could it be the 034 billet tranny mount I have ? I thought the billet rear diff mount could induce vibration, but the billet mount didn't do shit. Should I switch to the ECS in polyurethane ?

Video of the said rumble ; ( listen to the first minute) I heard the same sound, but also feel vibration (especially around the center console)

[PSUGOLD]

Can you hear metal vibrating with the windows open? My rear heat shield came loose and was vibrating like crazy, could hear it from the outside of the car too.