First off let me tell you when I competed in Powerlifting I always used a suit and knee wraps. Best I ever got 'raw' was a 465 squat in the gym. In a meet 550 with suit and wraps. Never used a bench shirt or deadlift assistance. Now check out these lifters. Found this link on Dr.Squat's forum. This lifting exposes what a joke Powerlifting has become meaning all the equipment has destroyed any resemblance of a sporting event.
My competitive lifting days are long gone but if you are going to compete, compete in one of these raw deals. Everything else is a joke. http://www.rawpowerlifting.com/videos.htm