You're right.
Actually it’s an M-18 Hellcat Tank Destroyer.
You're right.
Actually, you're exactly correct:
As we noted, the vehicle was an M18 Gun Motor Carriage (tank destroyer). Preston bought the TD in Denver in 1999 and enjoyed displaying it at car shows ("It's a 1944 Buick!") he would say, parking it in the appropriate area) or for charity fund-raisers. He painted his wife's name - Rachel - on the vehicle's flank.
The vehicle served in World War II for the US and had wound up back in the US after being surplused by the Yugoslavian Army. Preston, a school-trained mechanic as well as a pilot and philanthropist, also owned a DUKW amphibious truck, and, reportedly, an M5A1 Stuart light tank. He had owned a firearms dealership.
He told the Portland Oregonian once:
"The craziest thing I've ever done with it? At a car show in Portland, I showed up early and towed a 1984 Camaro with no engine in it into the middle of the grounds. Soon there were hundreds of cars there, and I had the announcer say "Would whoever owns the 1984 Camaro, please move it, or we're going to have it towed away." Of course, nobody moved it. With everyone watching, I fired up the tank destroyer and crushed that Camaro. The crowds loved it." . ... .