Does your GTS have the 4-pot calipers up front? If so the 300ZX TT pads should fit. You could also take out a front and a back pad, draw around them on a sheet of paper, don't forget to put them back in

and scan and e-mail them to a pad supplier, e.g.
www.discpads.com/default.asp to ensure you get the right thing.
Not sure about the shocks. You could replace the filter box with a K&N cone filter, or use a K&N panel filter. Not sure about the part # but you could e-mail them and ask. Measure yours and send them the measurements.