I am beginning construction of an Adire Alignment box. Design says to use 2 3"x11" ports. Parts express has a 3"x11" for $12.30 (PN 268-350) or a 3"x 11.5" port for $3.87(PN 269-932). Any reason to spend 3x as much for the 11"one? Would half an inch make any real difference? For amplification I have 2 choices, 1)An old Onkyo 80wpc@ receiver or 2)A plate amp from my Audiosource SW-15 rated for 200wpc. The Audiosource amp was my original choice mainly for convenience, auto turn on and no extra space on the entertainment stand. But I am concerned that it might have some type of bass boost or rumble filter. I have not been able to find out from Audiosource. This got me thinking the Onkyo might be a better choice. Even though it is rated for a few less watts I would think the amp section to be much more robust and higher quality than the Audiosource amp. Not to mention no concerns of a bass boost. I don't have the money to buy a dedicated amp so these are my 2 choices. What would you recommend?