Nothing, runnig the stock bose speakers off the deck till they give out. I have been throughly impressed by them actually. I know I can do A LOT better, but not much of a reason to replace them yet. Plus, that represents a huge investment that I'm not in a positon to make......YET!!!
When you are ready, take a look at CDT. They're a little high, but well worth it IMO.
1969 Chevy RCLB C10 350/TH400 SOLD
2007 Chevy RCSB 4.8 4x4 LS SOLD
2008 Chevy RCSB 5.3 4x4 LT SOLD
2010 Chevy CCSB 6.2 4x4 LT SOLD
2005 GMC CCLB DRW 6.6 Duramax 4x4 191,000 and counting
2013 FORD CCSB F350 6.7 Powerstroke 4x4