you can do 19's on a e36, its not hard.
18's are super easy to fit, but remember 235/40/18 is too big.
say no to shitty Chinese tires. (there are OK ones, though)
Hot: 2001 Estoril M Roadster
ZCP 19's, ZHP knob, JL 8W3
Cold: 2002 TiAg M3 6mt
ZCP 19's supersports, ZHP knob, UUC short shift GROM, OEM 18's w310's,
http://absolutehid.ca hid kit