what is this little box u speak of?? whats it called? i just got 2 12’’ subs and a 850w amp to push the pair but i really dont feel like buyin a new deck and from the sounds of it, puttin the new deck in, gettin a new faceplate, ect sounds like a pain in the A$$ someone help!!
1st… huh?
2nd… huh?
3rd… Welcome to the site!
4th… huh?
5th… you mean the speaker level input converter? If your not buying a new deck then you have to convert the signal into a signal the amp can use. some amps have a speaker level input. look through your documentation. If you do not have one you need to purchase one. I suggest going through your audio dealer.
I agree with Mark on points 1-4. If you’re a li’l more clear about what you’re trying to do, what you have, what you don’t have…we can help you better. 
- Darron
Welcome to the site… I’ve learned alot here and the main thing was
[b]BE VERY SPECIFIC[/b]