Add following manually in shoppings.dat file:
To section prices - section CarMods:
		exh_a_gr		BMBTE		respect 0 	sexy 0		600
		fbmp_a_gr		GRFBA		respect 0 	sexy 0		990
		fbmp_c_gr		GRFBC		respect 0 	sexy 0		990
		rbmp_a_gr		GRRBA		respect 0 	sexy 0		990
		misc_a_a_gr		GRMAA		respect 0 	sexy 0		500
		misc_a_c_gr		GRMAC		respect 0 	sexy 0		500
		misc_b_a_gr		GRMBA		respect 0 	sexy 0		500
		spl_a_gr_b  		GRSPA		respect 0 	sexy 0		900
		spl_c_gr_b  		GRSPC		respect 0 	sexy 0		700

To section shops - section carmod1 (to make them appear in the mod shops):
		item exh_a_gr
		item fbmp_a_gr
		item fbmp_c_gr
		item rbmp_a_gr
		item misc_a_a_gr
		item misc_a_c_gr
		item misc_b_a_gr
		item spl_a_gr_b
		item spl_c_gr_b

Add following in gta.dat file:
IDE DATA\MAPS\veh_mods\greenparts.ide

If you want to use the parts, replace string starting with greenwoo with this:
greenwoo, exh_a_gr, fbmp_a_gr, fbmp_c_gr, rbmp_a_gr, nto_b_l, nto_b_s, nto_b_tw, misc_a_a_gr, misc_a_c_gr, misc_b_a_gr, spl_a_gr_b, spl_c_gr_b