The 2 liter N42 Valvetronic was used in the e46 318i starting in 2002. Another engine used in the e46 318 was the dual-Vanos M44TU, which came in a 1.6 and a 1.8. If you have a 1.9 (more precisely, 1895cc), then you have an N43TU, SOHC 8V powerplant rated at 118bhp.
BMW usually offers M-tech or some other sports aero kits. I am prety sure I have seen e46s with them. What spoiler do you think you are missing? The trunk lid spoiler was an option that came with a premium, so if you don't have one, it very well may be because the original owner didn't think it was worth the money.
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