P1's are out there at the moment for 7K. Its the dogs danglies of all the classics and redisuals will always be good on them as a result, and certainly gets the thumbs up from any of the scooby fraternity.!
As for 2.5ltr they are great and the torque they give as a real world road car is second to none. So if you like a lazy driver and love instant pull then 2.5 all the way.
But if you like really spirited driving then a well sorted tuned 2.0ltr is a very nice car indeed. With a generally wider power band and a higher reving engine it makes for great fun. 400bhp has been done many a time on a 2ltr.
Some of the most fun cars I have had, have had the least BHP. And thats because they have reved like crazy and can thrash the nuts of them in most gears, handle like they are on rails, and maintain superb throttle response.
Keep an open mind, when the time comes, something will come along for the right price that will take your eye. IMO Focus less on bolt on extra's and more on service history, condition, and how much of enthusiast/genuine the owner is, and you will do all right. Oh and slightly contradictory, but don't always be infulenced by price.. sometimes it does pay to pay the extra to get the right example and will save you money in the long run.