Add following manually in shoppings.dat file:
To section prices - section CarMods:
		exh_a_zr		ZREXA		respect 0 	sexy 0		600
		exh_c_zr		ZREXC		respect 0 	sexy 0		600
		fbmp_a_zr		ZRFBA		respect 0 	sexy 0		990
		fbmp_c_zr		ZRFBC		respect 0 	sexy 0		990
		rf_a_zr			ZRRFA		respect 0 	sexy 0		500
		rf_c_zr			ZRRFC		respect 0 	sexy 0		500
		spl_a_zr_b  		ZRSPA		respect 0 	sexy 0		900
		spl_c_zr_b  		ZRSPC		respect 0 	sexy 0		700
		wg_l_a_zr		ZRWGA		respect 0 	sexy 0		500
		wg_l_c_zr		ZRWGC		respect 0 	sexy 0		500

To section shops - section carmod1 (to make them appear in the mod shops):
		item exh_a_zr
		item exh_c_zr
		item fbmp_a_zr
		item fbmp_c_zr
		item rf_a_zr
		item rf_c_zr
		item spl_a_zr_b
		item spl_c_zr_b
		item wg_l_a_zr
		item wg_l_c_zr

Add following in gta.dat file:
IDE DATA\MAPS\veh_mods\zr350parts.ide

If you want to use the parts, replace string starting with blistac with this:
zr350, exh_a_zr, exh_c_zr, fbmp_a_zr, fbmp_c_zr, nto_b_l, nto_b_s, nto_b_tw, rf_a_zr, rf_c_zr, spl_a_zr_b, spl_c_zr_b, wg_l_a_zr, wg_l_c_zr
