Import from GTA 4 by nik287, Sabbath Black, RIDERmaxCARNAGE:
http://www.gtainside.com/en/gta4/cars/28554-pontiac-trans-am-1977/

Credits to
baba0rum louping0 & SamuelT | nik287, Sabbath Black, RIDERmaxCARNAGE

Installation :
Phoenix files
OPENIV\update\x64\dlcpacks\patchday3ng\dlc.rpf\x64\levels\gta5\vehicles.rpf\

Handling.meta (you really need at last the center of mass if you want to keep your)
OPENIV\update\update.rpf\common\data