exhaust lagging

[Carl Pattinson <carl@flyers.freeserve.co.uk>]

Does anyone know what the current wisdom is on lagging exhaust 
manifolds.

It was reccommended at one time to reduce engine compartment 
temperatures, but was subsequently found to cause cracking of the pipes. 
I believe a compromise suggestion was to only part cover the pipes.

Does anyone have any advice on this.

The car racing fraternity do this as it allegedly increases engine 
power.

Also anyone know where to purchase Aeroquip fire hose (for insulating 
fuel lines) ?

CP