Excellent! So now you have both the 300 VR and 400 VR? Can't wait to see the images.
If the 400 VR is anything like the non-VR flavor, you will find the TC14 and TC17 are indistinguishable from transparent. I see only slight softening with the TC20. WOOHOO for you - an 800mm f5.6VR!:biggrin: Have fun you luck dog you!
tip re shopping the TC17. Haul camera and lens to a storefront and try several TC17 - there will ample variation (as I found with the TC20).