I always wanted to know what the difference is between these cars in terms of performance, does anyone have a video on them 2 racing, drag race or rolling start, Id love to know

 

Dragtimes.com has results. They are nearly identical.

 

The x350 is about 0.3-0.5 secs quicker to 60. Since the weight savings from the aluminum and the extra 20-30hp.

 

The 6th gear makes the biggest difference, the
weight and the extra power probably affect the
performance less than the better tuned ZF box.

Here is MT's quickest 308 XJR time, and C&D's
quickest X350(@40k mi), respectively:

0-60: 5.2, 4.7
0-100 12.8s, 11.3s
1/4 mi:13.7 @103.8, 13.2 @ 107