The standard JDM car runs 0.7 bar boost but, this is limited in 1st and 2nd gear, by the ecu.
The standard cars (GTiR and GT Four) do have very similar performance figure for 0-60 and 0-100 yes. I believe the standard GTiR times are 5.3 seconds and 14.9 seconds respectively ?!
The JDM WRC is 10 kgs lighter than the UK car but, it has 15 bhp more on the right fuel. 'The book' 0-60 time for the UKDM ST205 is 6 seconds from memory, not 7 seconds. That's the time for the ST185 !
As for the times, a boggo Evo 6 would do a 0-60 in 4.4 seconds and 0-100 in around 13 seconds. That weighs the same but, has 25 or 45 bhp and around 35lbs/ft torque more, depending on who you ask. So, there not so far fetched !
The major advantage of the GTiR, and the reason it manages manages the times/performance it does, is because it's so light. It's just a shame they didn't pay more attention to the weight distribution though as, that would have made it a stormer of a base fast road car !