Obviously, I know the VTF-15H is the most superior out of all the subs I have listed. However, I'm looking into upgrading and I want to know if it is worth saving for the most expensive sub HSU makes, or if I should go for the VTF-3 or 2. I would rather not go for the VTF-2 as my fiance absolutely hates the feet it has, so I'm not sure if her wanting the more expensive options is a blessing or a curse yet. I have an Onkyo TX-NR 709 and Pioneer SP-PK51FS. I'm using the sub that came with the system so whatever I get, I'm sure it will be a very noticeable increase in sound quality.