Is this chassis 33370171? If so, this chassis was for sale ex Pietersburg in 2005. Advertiser at the time said ZENDER E30 M3 bodykit. Chassis number stamped into body between wiper stalks on the firewall area will be definitive one to check. Looks remarkably similar to the old pic. had 180000km on it at that time.
Alpina branded parts include the instrument cluster, digital vent gauge (both made for them by VDO and engine sump plug and diffplug will have a sensor in it), engine mounts, alloy sump, gearbox mount, top radiator hose, wheels but see those look long gone already (made for Alpina by Ronal). drivers door jamb will have a green alpina tyre pressure label specific for "333i". Chassis tag above driver side headlight in engine bay will say "333i" AFM is mounted on a special body bracket welded to inside of wheelwell.
Steering wheel is standard Mtech1 and the gearknob is normal leather E30 BMW part with the dogleg shiftgate label in it.
All said and done if it's an original chassis may be worth the trouble. Try asking the guys who turned their nose up on original CanAm's or Capri Peranas 10 years ago because someone did something non-original??
Cheers
333