Bmw m5 burnout?

ok my dad has a 07 E60 m5 its a great car and everything but theres a problem. when ever we turn off traction control and floor it on a flat area theres no wheel spin until you get two second gear when it does that little screech. but when on and uphill angle it will burn major strips . so my quetion is how can we get the car to burn out on a flat surface like it would on a uphill surface. please answer thank you