Those two coils don't have the imaging. However, the 12.5" does....just some food for thought. Imaging is one of the best features of the GTI series. If you don't have many issues with mineralization in your area, I would suggest the 12.5" coil. That way you have the small (sniper), medium (stock coil) and large. Now DD coils as a rule poke a little deeper in higher mineralized soils. But, large coils don't fair well in trashy areas. More then one target under a coil can give confusing signal, or mask a good target. [size=medium]I have all three imaging coil[/size] and have used all of them. I mostly use the sniper and stock coil, but use the large coil in large areas with minimum trash. Hope this helps.......
Below is a link on search coils you might find helpful if you have not already seen it.
http://www.garrett.com/hobbysite/pdfs/searchcoil_tech_sheet.pdf