My new deck and amp install plus question about fine tuning 4 channel amp....

[YarisSedan]

So just swapped out my deck and amp from my acura. Didnt bother to swap out the subs not too much into that anymore just wanted a clean sounding system. I have 6.5 components in front and 6x9 coaxials in the rear. My question is how to best tune the amp. The stereo shop had the LP filter on the back and HP on the front. But i swapped both to full and it seems to sound a heck of a lot better. There is more bass now. I am asuming its allowing hp and lp so the component subs in my doors are operating fully and the tweeters are sending the hp signals.

The gain and hp and lp filters i am not too sure how to adjust those really. The stereo shop guy said he tuned them before he installed the amp but i know you need to tune it after really to reap the most benifits.

Below are the pics