sub filter

[DT]

Hi to all,

I am making this SMPS for my car sub.

My two paralleled IGC LM3886 pic1, pic2 .

And tis is the filter schematic i want to do for my sub amplifier.

so i hawe some questions about this filter.
1. How can i reduce PS voltage from + - 25V to + - 15V ? Maybe uA7815 / uA7915 will, or there is other (may be better) ways do this job?
2. Can i use this circuit without any changes to connect to paralelled IGC with 2xLM3886?
3. I just have some AD826's , can i replace TL072 with AD826 without any changes in the schema?

I am just beginner in electronics, so your help will be very appreciated.
And again, my english is very bad