You were saying... 
Laguna Seca Lap Times:
2012 Boss 302 LS: 1:39.50
2009 Audi R8 V10: 1:40.20
2008 Nissan GTR: 1:40.45
2010 Mercedes SLS AMG: 1:40.74
Here's the full list.
1. Dodge Viper SRT-10 ACR 1:33.92 138 '08 600 / 1536 Chris Winkler
2. Chevrolet Corvette Z06 Z07 Package 1:34.43 137 '11 512 / 1394 Motor Trend
3. Devon GTX 1:35.08 136 0 659 / 0 Devon
4. Porsche 911 GT2 RS 1:35.56 136 '10 620 / 1370 Excellence
5. Chevrolet Corvette ZR1 1:35.80 135 '08 647 / 1530 Motor Trend
6. Ferrari 458 Italia 1:36.22 135 '09 570 / 1485 Motor Trend
7. Nissan GT-R 1:36.35 135 '11 530 / 1736 Motor Trend
8. Lexus LF-A 1:36.39 135 '10 560 / 1609 Motor Trend
9. Audi R8 GT 1:36.39 135 '10 560 / 1520 Motor Trend
10. Porsche 911 GT3 RS 1:36.77 134 '10 450 / 1400 Motor Trend
11. Chevrolet Corvette Z06 Z07 Package 1:37.40 133 '11 512 / 1394 Motor Trend
12. Porsche 911 Turbo 1:37.80 133 '09 500 / 1570 Car and Driver
13. Mercedes SLS AMG 1:38.82 131 '10 571 / 1620 Motor Trend
14. Ford Mustang Boss 302 LS 1:39.50 130 '12 446 / 1573 Road and Track
And that is the LS edition (Laguna Seca) Which is not the 302 Boss.
Which includes a standard Torsen limited-slip rear differential, and revised suspension tuning.
So, that's a different animal than the 302 Boss.
In bold, I have highlighted the more current models of the cars you say the Mustang 302 Boss was dominating.
