volvo 850 Combi deeper / which mature ? / tyre stretching

Moin, eternally chewed theme, unfortunately in the threads a lot of scrap and nonsense. The following: car: Volvo 850 Kombi, ’96, 106 KW, 2345ccm ( HSN/TSN 9101 741 ) I have now a coilover suspension, should next week. ( TA- Technix ) Of course then comes up in better weather after the winter also a new set rims/tires. Now I have read and heard of course, rim dealers often seem to know no more than on the homepage. I would like to go a little bigger than the original ones, 17″ it should already be ( or the 16″ at max. lower setting of about 60mm). I would like to come low, however, do not know how that goes with the wheelhouse and the penway. Who knows? I would like to ride 16×8,5 with a “stretched” 195/40/16. ( currently 205/50/16 on 6.5) I think original volvo, which look like a propeller.) Which ET I have to consider ? ( what the TÜV says is not quite a bit more difficult.