No firsthand experience, but i've looked into it breifly too. Talked to ///JazzM about it a while ago. Problem with bmw motors is the distribution of the nitrous would be unproportionatly distributed, 3-5 would be getting too much nos, 1&6 getting almost none. This can of course be solved by getting a direct port nitrous kit, but then you start getting up there in price. Nos can be used in conjunction with other mods (like boost) for added gain (nitrous has a cooling effect on boosted motors).
Having said that, i definatly do not reccomend putting nitrous on a automatic 328. Mostly because there are much more effective mods you could do (like software, PM markD) along with intake/exhaust, or a 5spd swap.
Dave, same goes for you man. I love your car, and would hate to see it go prematurely.
Bottles are for babies guys
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