Regarding mustangs vs. anything else...
Look at the SCCA autocross PAX ratings for F-Stock and Super-Stock. Cars like the mustang, camaro, certain non-turbo imports (like non-turbo 300z), and other v8 cars are typically in F-Stock. The Vette is in Super Stock. Only the stangs and camaros with big mods end up in super stock, and they are simply not competitive against the vettes. In F-Stock, look at the national results, and you see that every year for the last 10 years, there hasn't been a mustang anywhere near the top 10. Again, there is not a stock mustang that is competitive against even a 1998 camaro Z-28 unless it is a limited run model, and even then they're not nearly as fast as an equal-price vette.
The SCCA results are definitive - these are real drivers of ALL skill levels, driving each of these cars on a variety of tracks to the limit of the cars. Some of these guys have been racing their daily driver for years, so you can bet that they are getting every millisecond out of the car. And the mustangs simply do not match up against anything comparable if handling is part of the contest.
In my very first SCCA autocross event, a very experienced mustang driver was racing against me in my brand new trans-am. I beat him in my very first race on the first day of the race weekend. The next day, he offered free driving lessons in exchange for co-driving my car. He won the event driving my car. There is no comparison on a real track between a stock mustang and stock f-body, even today. If you don't believe me, check the SCCA solo2 rulebook and vehicle classification guide and nationals results.
Of course, a well driven miata is about as fast as a mustang in solo2 competition... Just ask Andy Hollis
1982 Chevrolet Camaro Z28 305 auto 3.23 165@4200 240@2400 9.4 17.13@80.70mph MT 1/82
1982 Chevrolet Camaro Z28 305 auto 3.23 165@4200 240@2400 7.9 16.0@85mph CD 1/82
1982 Chevrolet Camaro Z28 305 auto 3.23 165@4200 240@2400 9.7 17.5@80mph RT 1/82
1982 Ford Mustang GT 302 4 spd 3.08 157@4200 240@2400 8.0 16.3@n/a RT 1/82
1982 Pontiac Firebird Trans Am 305 auto 3.23 165@4200 240@2400 8.8 16.75@80.50mph MT 1/82
1982 Pontiac Firebird Trans Am 305 auto 3.23 165@4200 240@2400 9.2 17.0@80.5mph R&T 9/82
1985 Chevrolet Camaro IROC Z28 305 AOD n/a 215@4400 275@3200 6.8 15.30@89.1mph MT 10/84
1985 Chevrolet Camaro IROC Z28 305 AOD 3.42 215@4400 275@3200 7.0 15.2@91mph C&D 10/84
1985 Chevrolet Camaro IROC Z28 305 AOD 3.27 215@4400 275@3200 6.9 15.30@89.1mph MT 10/84
1985 Chevrolet Camaro IROC Z28 4bbl L69 305 5 spd 3.73 190@4800 240@3200 7.5 15.4@90mph C&D 10/84
1985 Chevrolet Camaro IROC Z28 4bbl L69 305 5 spd 3.73 190@4800 240@3200 6.8 15.32@89.6 mph MT 7/85
1985 Ford Mustang GT 302 5 spd 2.73 210@4600 265@3400 7.1 15.51@89.7mph MT 10/84
1985 Pontiac Firebird Trans Am 305 AOD 3.27 205@4400 270@3200 7.7 16.07@84.5mph MT 10/84
1985 Pontiac Firebird Trans Am 4bbl L69 305 5 spd 3.73 190@4800 240@2400 7.6 15.6@87mph C&D 4/85
1987 Chevrolet Camaro IROC Z28 350 AOD 3.27 230@4000 330@3200 6.6 15.23@91.2mph MT 11/89
1987 Chevrolet Camaro IROC Z28 305 5 spd 3.08 215@4400 295@3200 6.6 14.9@95mph R&T 4/87
1987 Chevrolet Camaro IROC Z28 Conv 305 AOD 3.23 190@4000 285@2800 8.1 16.45@85.1mph MT 11/86
1987 Chevrolet Corvette 350 AOD 3.07 240@4000 345@3200 6.7 15.32@90.8mph MT 11/89
1987 Ford Mustang GT 302 5 spd n/a 225@4200 300@3200 6.5 15.13@94.1mph MT 11/89
1987 Pontiac Firebird Formula 305 5 spd 3.27 205@4400 285@3200 7.7 16.09@87.6mph MT 11/86
1987 Pontiac Firebird Trans Am GTA 350 AOD 3.27 210@4400 320@2800 6.8 15.35@91.6mph MT 6/87
1987 Pontiac Firebird Trans Am GTA 350 AOD 3.27 210@4400 320@2800 6.9 15.36@91.7mph MT 11/89
1987 Pontiac Firebird Trans Am GTA 350 AOD 2.73 210@4000 315@3200 7.1 15.5@89.5mph
1988 Chevrolet Camaro IROC Z28 350 AOD 3.27 235@4200 335@3400 7.2 15.67@91.6mph MT 9/88
1988 Chevrolet Camaro IROC Z28 305 5 spd 3.08 215@4400 295@3200 6.6 14.9@95mph Perf Cars 1988
1988 Chevrolet Camaro, Chevy Raceshop 454 454 AOD 3.27 400@5600 420@3600 5.5 14.0@102mph MT 1/91
1988 Chevrolet Corvette 350 4 spd n/a 245@4300 340@3200 6.5 15.04@93.6MPH MT 9/88
1988 Ford Mustang GT 302 5 spd 3.08 230@4200 310@3300 7.1 15.60@91.5mph MT 9/88
1988 Pontiac Firebird Trans Am GTA 350 AOD 2.73 225@4200 330@3200 7.3 15.88@90mph MT 7/88
1988 Pontiac Firebird Trans Am GTA 350 AOD 3.27 220@4400 330@3000 7.6 16.08@90.2mph MT 9/88
1988 Pontiac Firebird Trans Am GTA 350 AOD n/a 210@4400 315@3200 7.1 15.5@89.5mph
1989 Chevrolet Camaro IROC Z28 350 AOD 3.27 230@4000 330@3200 6.9 15.54@91.7mph MT 1/88
1989 Chevrolet Camaro IROC Z28 Conv 305 AOD 2.73 195@4000 295@2800 7.8 16.28@84.31mph MT 11/89
1989 Chevrolet Camaro, Chevy Raceshop 350 5 spd 3.45 345@5000 380@3600 5.2 13.7@103.3mph MT 1/91
1989 Chevrolet Corvette 350 6 spd 3.42 245@4300 340@3200 6.4 15.02@94.6mph MT 5/89
1989 Chevrolet Corvette 350 6 spd 3.54 240@4000 335@3200 5.6 14.46@95.27mph MT 11/89
1989 Chevrolet Corvette Callaway TT 350 6 spd 3.54 382@4250 562@2500 4.4 12.9@111mph C&D 5/89
1989 Ford Mustang GT 302 5 spd 2.73 225@4000 300@3200 7.2 15.77@92.8 MT 1/88
1989 Ford Mustang LX 302 5 spd 3.08 225@4200 300@3200 6.6 15.38@91.52mph MT 11/89
1989 Ford Mustang Saleen SC 302 5 spd 3.55 292@5200 327@3500 5.9 14.2@98mph C&D 5/89
1989 Pontiac Firebird Formula 305 5 spd 3.08 215@4000 285@3200 7.5 15.95@88.5mph MT 1/88
1989 Pontiac Firebird Trans Am 20th Ann 231 AOD 3.27 250@4300 340@2800 5.4 14.18@95.8mph MT 3/89
1989 Pontiac Firebird Trans Am 20th Ann 231 AOD 3.27 250@4000 340@2800 5.1 14.18@98.86mph MT 11/89
1989 Pontiac Firebird Trans Am GTA 350 AOD 3.27 235@440 325@2400 6.5 15.40@90.28mph
HERE'S THE LINK
http://www.cobranet.com/roadtest.htm