Are these any good?

http://www.autotoys.com/x/catalog/PA...CA_p_4930.html

If not, any recommendations on boosting a preamp line output? Thanks.

 

Probably OK, I've never used a PAC product. Pretty inexpensive.
Also see products from AudioControl, which may have more features and cost than you might want.
www.audiocontrol.com

 

I am using one of those PAC Turbo-1s in my Infiniti, it has worked well for me and I would install another one if the situation ever came up. You can get it even cheaper (~$20-25) if you look around.

Company website is www.pac-audio.com

 

If you wanna put some aftermarket subs on a sealed enclosure, can you splice into the speaker leads of the OEM subwoofer and feed it into your LLC or do you have to splice it when the signal is low power?

 

You use the speaker leads as the input to the LLC - that is its purpose.

 

I am looking for an LLC also. Looking at the Audio Control website, I think you would get more options with the LC6 and EpiCenter