I have a VTR too, I thinned the ring to fit my Kayfuns rather than cutting it off.
If you don't want to modify the ring then you are severely limited in which atomizers you can use without having to use the ridiculous extension tube.
I would suggest getting a Cloupor instead. 30W gives you far more options for what you can do with it. I hardly use my VTR since getting a couple of Mech Mods.
It is fine with the Kayfuns and other single coil builds, but any decent dual coil setup needs more power to get decent performance. (RTAs such as Fogger and Orchid use dual coils)
As readeuler says, if you do ever decide you want to use an RDA on the VTR, you are forced into using higher gauge wire which has less surface area in contact with the wick compared to thicker gauges.
Another similar option is the Hana Mod Clone...
$49.00 HANA MODZ Pack DNA 30 Style Mod - 1*18650 / 7W-30W / battery not included at FastTech - Worldwide Free Shipping
(Always check the reviews and discussions if buying from Fasttech)