Yup. Biggest difference being where the power comes in and lasts due to the different turbos. The suspension is a bit stiffer and short shift gearing.
The thing is i've now got that P1 turbo fitted to mine along with some sti6 typeR v limited suspension, so in summary UK all the way
Hindsight being the great thing that it is, i'd probably have bought an import, would've saved me puting a load of jap bits on mine, but when i bought it, it cost me £12.5k and i wanted a dealer warranty at that time thought all imports were dodgy (why would anybody buy an import when you can get exactly the same car in the uk, hindsight again )
In fairness though, surely with regards to classics, you could only compare a uk turbo with a jdm wrx and not an sti. Or a P1 to a typeR.