I finished my modifications last nite and since then watched several bass heavy scenes from different movies and listened to my favourite CDs. The difference is night and day, even to a person who isn't an audiophile, i.e., me. I stuffed the sub with about 15oz. of polyfil taken from a pillow, and added four spikes. Ended up with lower SPL with pre-mod settings, adjusted the gain to read same SPL as b4 and there we go; the sub hits much tighter and I am definitely sure that it plays lower notes now. Stuffing the polyfil is very straightforward and has been covered in many previous posts, but one thing I have to add, if you use loose polyfil like me without glue or staples, when you work on the left side wall of the sub try not to leave the cables going to the driver between the polyfil and the wall. I did that way, leaving the cables, and was lazy to pull all the stuffing back and do it once again and I think I'll have to open it later on to check if the cables pulled the polyfil when I replaced the driver. One thing about adding spikes; on the front left corner inside the sub, behind the on/off swithch, there is a small unit. If you intend to screw the spike from the point where the plastic foot is, use a short screw. I used a 16mm one for that corner, 20mm for other three. Pull the plastic feet off as they don't let the screws go in properly unless you screw them with a drill. If you place the spikes to a point inside the feet, that's fine as well but I felt the balance would be better when spiked closer to the corners. Use strong spikes as the sub is heavy. Finished in 45 minutes and it has been a big upgrade, just do it if you haven't done already!