Add following manually in shoppings.dat file:
To section prices - section CarMods:
		exh_a_ku		KRMEXA		respect 0 	sexy 0		600
		exh_c_ku		KRMEXC		respect 0 	sexy 0		600
		fbmp_a_ku		KRMFBA		respect 0 	sexy 0		990
		fbmp_c_ku		KRMFBC		respect 0 	sexy 0		990
		spl_a_ku_b  		KRMSPA		respect 0 	sexy 0		900
		spl_c_ku_b  		KRMSPC		respect 0 	sexy 0		700
		wg_l_a_ku		KRMWGA		respect 0 	sexy 0		500
		wg_l_c_ku		KRMWGC		respect 0 	sexy 0		500

To section shops - section carmod1 (to make them appear in the mod shops):
		item exh_a_ku
		item exh_c_ku
		item fbmp_a_ku
		item fbmp_c_ku
		item spl_a_ku_b
		item spl_c_ku_b
		item wg_l_a_ku
		item wg_l_c_ku

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

If you want to use the parts, replace string starting with blistac with this:
admiral, exh_a_ku, exh_c_ku, fbmp_a_ku, fbmp_c_ku, nto_b_l, nto_b_s, nto_b_tw, spl_a_ku_b, spl_c_ku_b, wg_l_a_ku, wg_l_c_ku

If you want to use those as addon, change admiral to kuruma or any desired name.