It's funny this surround mix got slated by some quarters back when.. for me it's a triumph! I've heard Marvin's back catalogue zillions of times (another artist I have everything of, I looooove that voice.. It's such a gorgeous instrument hard in the Centre) and yet this Surround Collection (for that's what it is, I guess the producers didn't put it together as such, it's origins being on DTS CD solely in 5.1.. and I didn't buy it for the zillionth stereo mixes and I imagine I'm not alone in this!) really takes this overfamiliar material and utterly transforms it!
FWIW, there's a few Motown DVD-V Video collections of various artists (incl Marvin, Four Tops, Temptations) which have some 5.1 and a Capella mixes where you can isolate the lead vocals in similarly spectacularly spine-tingling fashion.
The Motown DVD's I'm talking about include..
This:
http://www.amazon.co.uk/gp/product/B002QVTBEM?
and this:
http://www.amazon.co.uk/The-Four-Tops-Definitive-Performances/dp/B001G9LVB6
and this:
http://www.amazon.co.uk/gp/product/B001O1ADC4?
and this:
http://www.amazon.co.uk/Marvin-Gaye-Thing-Performance-1964-1961/dp/B000EU1LKE/