Get the $50 ground isolator from Crutchfield, it's worth it, especially
in a Westy where running wires is a PITA!  Works fine with high power
systems, it balances the load across all four channels into a single
(combined) speaker ground connection .  Personally, I think it is better
than individual wires and one heluvalot easier to install!  You'll be
listening to your stereo in about an hour.

--
Stuart MacMillan
Seattle

'84 Vanagon Westfalia w/2.1
'65 MGB (Daily driver since 1969)
'74 MGB GT (Restoring sloooowly)

Assisting on Restoration (and spending OPM):
'72 MGB GT (Daughter's)
'64 MGB (Son's)

Stripped and gone but their parts live on:
'68 MGB, '73 MGB, '67 MGB GT