AGE has EVERYTHING to do with it rob. i know it, insurance companies know it, but apparently some people here don't---and they're usually under the age of 25!!
young males are more likely to drive reckless, that's why their insurance rates are highest. i've owned my '87 mustang GT for 11 years--my insurance went down when i turned 25, then it went down again when i got married. the insurance company has done the research and knows that older people are less likely to drive recklessly and cause accidents. driving recklessly includes everything from run-of-the-mill speeding, to burnouts, drag-racing, etc.
austin's blue C5 Z06 was fairly close to stock---sam's car was modded to the hilt. you're comparing apples to oranges. if you buy a heavily modded car, you had better look it over with a fine-toothed comb and suspect it was driven hard.
when buying a used car, you should always ask very specific questions about how the car was cared for, and see how the owner responds--if they seem shifty, or you suspect they're lying, then you should move on.
but not knowing anything about the person (other than age), who here would buy a sports car (say a corvette) from a 22 year old male, over a 45 year old guy???