Some of the low frequency rumble is the fact it is a hatch. All hatches are more susceptible to make a deep rumbling sound due to the shape of the interior.
the fact your car is missing that hatch bit which goes from seat to rear covering the cargo space probably makes things worse.
that piece really IS a part of the car. and no way should it be missing.
Also fill up the cargo space with a bulky item. a thick blanket in there would cut the rumble some.
I am very aware of the deep rumble noise this car (actually any hatch) makes.
Like I mentioned, sticking sound dampening bulky stuff into the cargo space can reduce the rumble.
Last edited by Elizabeth; 02-26-2013 at 01:47 PM.