Running costs will be higher than the clio no doubt and as for reliable engine wise im very sure they are. In the last year i had to replace full brakes,suspension shocks/springs, exhaust system 1 set of front tyres and 2 sets of rear tyres so far its been fine lol, as for the n\a not being much quicker than the clio think toyota said the n\a was 6.2 0-60 top end of around 150 which is no slouch
Ph.1 172 0-60mph is 6.8secs 0-100mph 18.3secs (can't find weight but think about 1050kgs)
Ph.2 172 0-60mph is 7.1secs 0-100mph 18.9secs 1110kgs
172 Cup 0-60mph is 6.7secs 0-100mph 17.7secs 1021kgs
Clio 182 0-60mph is 6.6secs 0-100mph 17.5secs 1110kgs
182 Cup 0-60mph is 6.5secs 0-100mph 17.3secs 1090kgs
Trophy 0-60mph is 6.6secs 0-100mph 17.3secs 1090kgs
Clio 197 0-60mph is 6.9secs 0-100mph ???? 1240kgs
197 Cup 0-60mph 6.9secs 0-100mph ???? 1220kgs
Clio 200 Cup 0-60 6.6secs 0-100mph 16.7secs 1204kgs
that shows the supra n\a on data is faster than the quickest clio and the supra weighs about 400kg more all im saying is dont discount the n\a many people are happy with it and its a big jump from a clio