I have had a lot of cars over the years including a V8 Monaro and I can honestly say my Cougar is the best car I have owned. Maintainence is no worse than any other car, remember Cougars are basically a two door mondeo, and there are plenty of them around.
Also modifications are relatively cheap and the cars look great and really get a lot of attention.
Be prepared for people to come up to you in the street and ask you "What kind of car is THAT?????"
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As regards tyres you are only going to replace them every 100K anyway (as long as you look after them).
Mate, you can't go wrong they are great cars.