I had a ARP4 for a couple of years and had a lot of fun. Its not always an easy drive and you have to know what it is excatly and be sure that is what you want.
Its doesn't have much low down torque but does deliver the torque that it has smoothly and in a linear fashion with no flat spots. It revs and revs and at over 5,500 rpm starts to fly. On a good day and if you like a revvy naturally aspirated engine you will have more fun in an ARP4 than almost anything else you can buy at the price. On a bad day .. Well lets just say its not always a pleasure to change down 3 gears to overtake someone and I didn't like to have to always wear earplugs on a long journey.
Despite claims of poor consumption I averaged around 30 mpg with a low of 25 mpg. That wasn't particualrly hanging around and I only ever drove it when I wanted a spirited drive.
I now have a Plus Four AT which is of course faster (with its massive 400Nm of torque) but if I am honest has nothing like the sporting appeal of the ARP4. I still think of memorable drives in the ARP4 whereas in 12 months I still haven't had such an intense experience in the Plus Four - even though its ferociouly fast for a 2.0l car. The Plus Four is just an easy 'no bother' kind of car whereas the ARP4 makes you engage with it on its terms or simply tells you to sod off!