When you strip it all away the cabin of the Evora is effectively a composite bath tub with the acoustic qualities to match so it’s not surprise it’s a bit boomy. It’ll take some doing to reduce this but why not try?
I have used (off Amazon) Canopus sound deadening material on the inside of my doors and the sub enclosure. It’s self adhesive and easy to work with. I wouldn’t know if it’s the best on the market but it did the job for what o was after.
I’d say that under the back seat and behind it would be a good place to start. Then the floors, underseats and doors etc.
in terms of weight, it is around 4kg for every 10sq ft. I get the comments about weight but I’m 72kg, and no one seems to suggest that a driver who is 80kg makes a substantial difference to a car and if it’s that much of an issue one can leave a couple of gallons of fuel out to balance it out Besides, having the weight at floor level would reduce the centre of gravity by a fraction of an inch to compensate.
The only thing is that if you do this and don’t like it, it will be a pig to unstick it all. I really wouldn’t fancy that job.