The quoted figures on GT4's are a bit hit and miss. The ST205 was quoted 239bhp and 224lb/ft on the UK car and 255bhp and 224lb/ft on the JDM.
Mine is totally standard and has 100, 000miles on it and got 260bhp and 253lb/ft at the Pulsar RR day at Prosport. I only had it a couple of days at the time and it was misfiring big time and needed a service. All sorted now so god knows what it has.
Here is a "Best Motoring" clip. I need to find the full video.
http://www.youtube.com/watch?v=uj8-fBC6XHk
People go on about them being heavy but they are 1380kg which is lighter than todays evos and scoobies I think (???)
Handling is fantastic with 50/50 torque split and a rear lsd and a viscous centre diff.
Brakes are amazing. The only production car at the time to have a shorter stopping distance was the Mazda RX7 (3ft shorter).
For 1/4mile then the GTiR would get my vote.
For driving then the GT4 is far better to be sat in.
Here is the Top Gear vid of the Escort Cosworth vs the Celica GT4 ST205
http://www.youtube.com/watch?v=BQj21_0tK1o