will this system be ok?

[HTX86chevy]

ok, i have a 1986 swb c10. here is what i have: Sony xplod deck (rms output 17watts- peak 52 watts) , the dash speakers are kicker factory replacements that sound like crap with the bass a level 2 on the deck. the rear speakers are 6x9 jvc's (80 watts rms - 510 peak) i have an amp for the 6x9's that is a kenwood (350 peak watts- 60pms) also have an amp for a subwoofer that is also a kenwood mono class d (600watt peak - 200 2x1 rms) <~dont know what (2x1) means.

any suggestions on what sub i should purchase? im really cheap when it comes to the sound system , but i would like it to sound nice..... not at all at competition level, but something enjoyable as this is my daily driver.

Should i connect the dash speakers to the amp as well or just disconnect them?
would everything "flow" together nicely or did i waste my time/money. im new to this so any advice would be helpful.