stripped out interior (no rear seats, no passenger seat) hks cold air intake with cold wrap, turbo injectors, exhaust muffler and damn good skills
You are not gonna be able to get an accurate answer due to the mods you have made and the little bit of weight you have removed.
Also, you didn't say what year the car is, or what size engine you have. Depending on what year it was, BMW did some screwy stuff with there designations. Some years 328 was a 2.8L, and some years it was a 2.5, and some years it was a 3.0. Without that, there is no way to get an answer. You could google "BMW 328i (and add your year)" to get ballpark stock numbers, and subtract from there for your mods. Still, your best bet is to just go to a "Run what you brung" open track night and see. Because no matter how honest you try to be, people tend to overestimate how much they gain from simple mods. You will not gain 1 sec from losing 100 lbs. A second is alot.
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