liquid nails rocks for sub boxes i built one of mine using the stuff works a treat. but dont forget to use a few wood screws too to hold it all together! lol
my 2 type r's weigh in at just over 13kg. so times that by 2= 26 kg. then add a further 20 odd kilos for the box (mines fair big and 16mm mdf all round)and thats 46kg. its like having a light weight 2nd person in the car all the time!