Celica problem might be as simple as a vibration or heat shield rattle, or something much worse and a complete nightmare.
Colleague of mine has a 2003 Celica VVTLi (the 190bhp one) and the engine went pop in that with only average mileage on it, they seem to be a car you need to abuse to enjoy - only really shift when you're doing 6500-8500rpm on the second cam. Guess a lot get ragged
Hate to lower the tone but the mrs was right, you could do a lot worse for your money than a Mondeo