Here is the list of Gruppe M's products for the NSX, taken from the 1999 catalog. Price in JPY
ENGINE:
super charger 1500000
muffler 280000
header(same as DC sport)250000
test pipes 50000
K&N cone filter ?
K&N Japan Carbon Fiber filter ?
K&N Japan Special air cleaner(the one you have, I also got one too
) 88000
NA1 ECU 120000
NA2 ECU 180000
BODY PARTS:
front lip spoiler ver.1 68000
front lip spoiler ver.2 68000
half cowl spoiler 200000
front ground effect board 120000
air duct bonnet 280000
side step 150000
carbon side duct 68000
over fender 120000
rear wing 180000
rear wicket spoiler 68000
rear under cowl 180000
carbon engine hood 98000
carbon mainfold plate 18000
aero mirror 128000
CHASSIS
rear strut bar(same as DC sport) 58000
springs 80000
suspension set 280000
I didn't list interior stuff such as shift knobs or hub adaptors. There are also other minor stuff like rims, a engine hose kit and a brake kit that is in development.
Contact Alex V. if you want to buy any Gruppe M stuff. He is a personal friend of Mr. Ogose(The M). Also see my website for more info:
http://www.geocities.com/Tokyo/Dojo/6073/index.html
I will scan the catalog for all to see later.