noob question - please

[hmmyip]

I am new to all this, though have been researching it for some time,
(I like to get all the theory straight in my head before I try the practical!)

I have a few questions and I hope someone can answer them.

I have been looking at various roms for my year/make/model car, which is a 2002 sti prodrive type UK with PPP.

The rom is a A4RG060Q and I have downloaded it successfully from my car.

I also have the same rom image from the scoobypedia site to compare it to and its identical, no real surprise there.

Ok, I have also looked at various roms on here, there is a MY02-STI-UK-PD.hex which is a rom image from the same type of car (afaik) of rom type A4RN1000.

So to my question, why does my rom not show any different to the standard rom? ie there seems to be no difference in the boost maps, fuel maps, ignition maps from standard.

Is this because the 'Prodrive chip' can not be read from the rom, and alters the maps on the fly? (if you get what I mean)

If this is the case am I ok to alter the maps (not something I am going to rush into!) even though I can't see what the P'drive chip is doing?

Thanks for any help, this has been the best website for learning all this from!