remap is a starting place to get more throttle which is limited in the lower gears, also improved curves. Abbey or RS Tuning are two companies that can help you out with this.
yep still available, first post here viewtopic.php?f=9&t=12347 is kept up to date
Sadly no individual username ones available but like others have said, perhaps rtbiscuit could sort something out for you
i think the system if detecting a fault (ie one of the airbags has been disconnected) then it turns off the whole system. Airbag error light will also be on on the dash