GT6 Rear Springs

[GHaynesTR4@aol.com]

I was planning to upgrade my Mark I GT6 to the later swing spring setup when 
someone mentioned coil-overs for the rear (retaining some part of the leaf 
spring, 
of course).
Does anyone have knowledge/experience with coil-overs for the rear?  We'll be 
driving this car on the street and autocrossing it occasionally.
Please reply directly, rather than to the list.  Many thanks!
George