Everything you ever wanted to know about the subject:
http://www.cirp.org/
A good site I found awhile ago.
I find it interesting that most of the comments here have been "against", but yet the poll is a majority "for". Go figure.

__________________
past MB rides:
'68 220D
'68 220D(another one)
'67 230
'84 SD
Current rides:
'06 Lexus RX330
'93 Ford F-250
'96 Corvette
'99 Polaris 700 RMK sled
2011 Polaris Assault
'86 Yamaha TT350(good 'ol thumper)