The caterhams dont own many of the circuits in this country, yes they are quick but a quick reccy of lap times will show that the nose heavy cobras and things like the nose heavy fancy new corvette stuff them good and proper on many tracks. That shite on top gear is hardly a bench mark, things like the veyron would eat the caterham on many circuits but is not at home in a slalom. If you took a caterham to lemans it would probably need another day on the track to complete the same race distance.
I did put a calculator across the subject and even the lumpiest engine you could put in a roadster only increases the total build weight by 5% so It wont bother me.
If I lost a few stone it would make more difference.
Bob