dan i can be the viper suspect if you like. i'm happy to volunteer my car or ecu (i have a spare ecu with standard chip i can put back into mine) if anyone wants to do tests. May just be the ecu by the time you'd get around to this as i expect the new engine will be in. Also would turn up for a rolling road day for sure.
BBR are pretty cool fella, dont believe you've never heard of them! they have a massive motorsport history, David Brodie was a touring car driver in rs500s i think!
they did the BBR mazda mx5 turbo which was distributed by mazda as a proper model with a mazda warranty, lots of cossie tuning (still have a fast lane mag somewhere where they have an escort cossie that does 0-60 in under 4s

), a golf turbo conversion and loads of other stuff.
i had a gander at their website and the e30 318is isn't listed as a model they do a starchip for though, only the e36. maybe they used to do it? you should give them a call.
http://www.bbrgti.com/StarChip.php

2.1 318is, MS, LPG. 200bhp, 175ft/lbs GONE!
Boxster, e46 m3, e36 sport touring and alpina B3 3.0