The P1 uses a jap Sti engine, with the ECU slightly tweeked for UK petrol. The only problem is they didn't tweek it enough. Most P1s have had an engine rebuild at some stage because of this.

Standard they will be around 280bhp. You ideally want to get one that's been either remapped pretty much from new(negating the ECU issue), or buy one with a rebuild which has been mapped. One running in standard form would not interest me in the slightest, as it's an engine failure waiting to happen.