The primary goal with the GTR was to make an accessible supercar that anyone could drive fast. To that end you want a very stable car with a lot of natural mechanical grip. That means weight distribution is very important to keep the handling neutral and the more weight you trim the harder it becomes to place it where you need it because you can't put the cylinder heads in the trunk for balance. The GTR has a 53:47 weight distribution front to rear, which can become 50:50 with a bit of throttle applied. Grip from the tires is mostly a function of how much weight they have pressing down on them so a heavy car has a lot of natural grip, even if it's ultimate limit is hampered by the extra weight. A car with a lot of natural grip is generally easier to drive because it's not dependent on weight transfer or downforce to push the tires down and give you traction. To use the extreme opposite example, I had a go in a Lotus Elise once and while it is very quick it's also a tricky bastard to drive to fast. Quite a bit of understeer until you get some weight on the front with the brakes or shove the back out with the throttle, at which point it's requires a fair bit of balancing on the throttle to keep from ending up backward.
