I have fiitted two towbars myself to my VE SV6 sedan a few years ago. The first was a 1200Kg bar, and the second was a 1600Kg/ 2100Kg bar. The 1200 Kg bar is shorter reach into the chassis rails than the 1600Kg and from memory only two bolts each side. The 1600 Kg bar extends further into the chassis rails and there is an extra bolt that is above the rear mufflers (so mufflers need to be removed to fit the 1600Kg bar). If the gas tank is mounted to the chassis rails close to the rear of the car then it would affect the fitting of the bar, but it could well be that it mounts through the same holes as towbar bolts are installed. To fit a towbar to a VE sedan doesn't require any drilling, just appropriate bolts. I couldn't say differences as far as a gas wagon goes.