I'm a lambo lover aswell and this car is a beast when it comes to sprints...
The stock tuning is incredibly stiff in turns because of the stabilizers and toe angles, ofcourse it could also just be due to the fact it's got a massive V16 engine(two V8 units in one) sitting over the rear wheels.
You could toy with the weight balancing and set some more at the front end but I would recommend buying some lightening kits first(its a real massive car)... Theres also a better method of fixing it with the suspension. After you purchase a racing suspension try these settings...
Spring Rate: F/R (10.0/15.0)
Ride Height: F/R (90/90)
Shock Bound: F/R (5/7)
Shock Rebound: F/R (5/7)
Camber Angle: F/R (3.5/1.0)
Toe Angle: F/R (3/0)
Stabilizers: F/R (1/3)
Note: The toe angles and stabilizers are very important...
The brakes are just about the worst factor in understeer so grab a balance box and set it to 2 front and 10 rear. Dont worry about losing it with this car becuz it's incredibly wide and stable with alot of weight towards the back.