i have o 07 gxp i wish i would've never bought it. battery already died last winter 140 to replace. have get it aligned every 7000-10000 miles or you start eating up tires. to replace brakes just for parts its about 550. transmissions aren't known to be the best. over all they're a expensive car to work on.
i do see around 26-29 mpg on the highway and the passing power is nice.
go to ls1tech they have a section for them called ls4
i do see around 26-29 mpg on the highway and the passing power is nice.
go to ls1tech they have a section for them called ls4