In regards to your shifter…
1) the kit Jim linked above is no different than one of IE’s kits. The idea being you run the later 2002 hardware and a later bmw shift lever. Toby and I like to verbally chastise each other on our differing opinions on early vs. late shift hardware.
2) Given your race car bench mark…. it won’t happen in a street2002. You can improve a sloppy 2002 shifter with kit(s) like the one above (also recommend replacing the two shift plate mounts and support rod bushing) and get maybe %50 towards your benchmark. It’ll never feel like an s2000 though.
3) You can go with a tunnel mounted shifter like AKG or bimmerworld, but while the shift lever itself will be planted feeling, you’ll need urethane motor/trans mounts to similarly stiffen the drivetrain.
In short, there’s no golden bullet. Your friend may be well-meaning, but given your benchmark, perhaps it’s not the best advice.
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On the panels, yes on later green clips.