Jaba, the plot thickens! the aircraft you speak of is for sale:
19-XXXX 45 hrs TT, Superior IO-360 180 hp, Sensenich metal prop, 150 kt @ 28 lph, 3,000 fpm climb. Analog panel contains ASI, VSI, ALT, Tacho, oil temp, oil pres, 4 way CHT & EGT, G-meter, fuel pres, manifold pres, amps, volts, 2 fuel gauges, Icom A210 VHF with intercom, Garmin mode C transponder, SIRS compass, key start & glove box. Dual brakes, electric flaps, sliding canopy, leather upholstery. Price reduced due to unpainted. $140,000 + GST. Will deliver. Ph XX XXXX XXXX
No mention of a single seat limitation and no hope of putting it into GA experimental for the new owner, the best you could hope for would be for 600 kg's to come along, but this has not been approved. Probably the reason why it came on the market I guess.
IF 600 was the MTOW - 430kg BEW = 170kg payload.