From the pictures it seems to be a VL Calais Series 1
Series 1 (1986 some 1987) had the headrests like that and a few other things such as door skins, and a few other different interior bits a pieces.
The series 2 (late 87 and 1988) had full padded head rests.
Turbo badge on the back or not won't help you, vl's are one of the most stolen cars in aus. btw good luck with the sale
you also stated original turbo was highflowed, for anyone interested that would be a t03 highflowed