The original model "the 287ps model" had more torque than its younger brothers.
The 2nd model is "the 300ps model" It came out in 2006. Sometimes referred to as the "revup engine" It has a higher rev limiter and a facelift interior and headlights(now bixenon) and led tail lights. The interior was a bit of a let down in the original model according to reviews and the facelift is much better design and quality.
The 3rd model came out in 2007 "57" plate if i remember correctly. It had a full overhaul of the engine which now has 2 intake ducts and is referred to as the "HR" engine. It is the exact same as the 2006 facelift model but with the newer engine. It also has a bonnet bulge to help house the new engine.
All uk models were of a gt spec which included rays, leather interior and bose sound system. The pre 2006 models sometimes never had the lightweight rays though as they were an optional extra up to a point.
Even though these cars vary in power, they are very much similar and the differences in the newer models are much less noticable. The 2006 onwards models have the higher tax band of 400 odd quid
I hope this helps you out and welcome