Re: GTA arches?
a couple malaysian 156/147 have had the GTA treatment. it's a lot of work - front rear bumpers and fenders have to be changed. swapping the rear fenders involve cutting near the roofline and rewelding on the wider arches. not a cheap thing to do.
and yes, fitting GTA bumpers onto a stock car will make it look weird.
the blue 156 with the GTA conversion was a taiwanese car. belonged to Lancelot if im not mistaken.
zender front & rear bumpers and cadamuro skirts will get u looking close to a GTA, but not quite.