We were going to take the spare wheel out the front of my mates MR-S & do a similar thing. But we decided it would sound awful with too many vibrating bits in the bay. There's now a more conventional 2x10" set up in the cubby holes behind the seats.
record the sound of a ferrari scudoria, or the ascarri v10 reving, then at the lights, turn the radio up full blast and play the recording, no 1 will race you