Does anyone make a "drop in" sub box (like the thunder forms) for the standard cab Silverado?

 

I have a extended cab box from thse guys.
Quality was real good.

I was looking for a box for my reg cab but am going to build one due to my amp.
They have 2 10's 2-12's
single 10, 12 ported and the superbase version.
http://proboxrocks.com/chevy/99upregular.shtml

The finish reminds me of Rhino lining.

The guy who answered the phone was real cool and spent some time with me and my stupid questions.
here's the one they recomended but have differant versions available

 

https://ls1tech.com/forums/showthread.php?t=197101

In case your interseted.

I would sell the box seperate for $50.00 plus shipping