Stealth chip update

[Smudge]

This may have been covered before but I thought I'd ask as once again I'm not searching effectively enough.

Can someone tell me whats involved in upgrading to a stealth chip on a '99 AU 1 XR8?

Whilst speaking to a performance shop about some upgrade options for street dragging (at Motorplex, not the highway!), we discussed a "stealth chip" upgrade which involved flashing the original chip with new instructions. But I'm not sure what else might be done and forgot to ask.

My understanding of computer chips and flash"able" ROM is that you replace an existing instruction set with a new one...thinking about this step alone I'm stumped why it's expensive (to me!), unless thats the software R&D component.

So if anyone knows and wants to tell me I would appreciate it - even though I'll prolly end up doing it anways...after the cold air induction and replacement extractors go in

Cheers,

Smudge