If you have a spare $250, you could buy a SEB228 PN, that's the best of the lot that miele offers (developed by Wessel Werk I think), it's nothing like the Tristar (especially mine) or Sebo PNs, but it's a start...
And if you want better airflow, swap the bags with GN bags, they're bigger thus allowing more air to filter through, not got a clue about the pre & post motor filters though, they're pretty restrictive given that they're not pleated or anything... :\
It's funny, that one looks identical to my S316i, same colour and everything, only I nicknamed mine the "Red Baron"... 