back box for b4

i,m looking to get a nice rumble from my b4 without going boyracer loud . just from the diff back would do . something that,ll fit straight on . any ideas .. also what happens to the little solenoid thats on my original box . ?

what have you on at the moment?? i have just the standard back box and theres a nice rumble off it, nothing too loud

i got an exhaust of damo in street performance for my b4. theres a nice rumble from it but when drivin on the motorway or crusin along its fairly quiet.