PS, lots of the cars you mention won't use proper stretch bolts as standard like the cvh. Most of the above will probably have ali blocks and ali heads... no need for stretch bolts to account for different expansion rates.... they could use them to negate automated machine intolerance (over tightening to a degree won't effect clamping forges as the bolt stretches by a predetermined amount).

After a bolt has gone plastic (a perminent change to shape) its next to useless.

Stretch bolts are used for numerous reasons, differential expansion, tightening tolerances, but essentially the are used to maintain a certain clamping force, regardless of gasket 'squish', material expansion/contraction etcetc.

If you don't use the stretch bolts a re-torque is essential.

Rob,