Here we go... apologize my English, but I will try my best. So to give you some back information. Bought this car about year and a half ago, did some chip tuning, exhaust and intake work just for daily driving. Some time later I felt like why not add a small subwoofer in the car and bought SPL Dynamics amplifier with Ground Zero 12" sub. Well the sub never made it to car.
So I kept the amplifier and bought some 15" Autostudio sub with recone, it was around 1kw RMS. Also some quite good quality enclosure.
It was satisfying about a month or two .. but well you always want more. So I went and ordered 2x15" GS Audio platinum subs 1.5Kw RMS a piece. And started building my own enclosure for them. Made it a little bit too small because my plan was to fit it behind the seats to compete in Street class. That quite didn't work out. Also at that point I started sound deadening car's trunk.