supernova

Hello I would like some advice as im new to subaru imprezas,im very interested in buying a 2005 Impreza 2.0 turbo Awd saloon but ive noticed there are also 2.5 turbo engines also available my question is what is the best engine all round ,il be using the car for commuting to work (around 60 mile round trip a day)not including weekends,what should i look out for on these models when buying second hand?many thanks in advance for any advice,Regards Tony