It is an 'old school' exhaust for the 5, i remember my cousin buying one for his 5 in '94 and loved them.
I would of suggested looking on nDevil website but you have already, if there not there then there not made anymore which is a shame. Alot of exhausts aren't made for 5 anymore, if your lucky you may find one secondhand.
Devil did make a side sxit exhaust but this was for the 'cup series' cars only so very rare indeed.