Compression Ratio

[x444wrx]

I as many know have a 2007 sti ppp, what is the standard compression ratio on the GDF 2.5l units? got my eye on another set of pistons but just noticed that the compression ratio is different at 9.2:1 where as these pistons are also available in 8.2:1 will it matter much about the compression ratio as obviously the car wont be standard and will be getting re-mapped again to suit new set up / engine build in the future. Cheers