The similarities between 2002-04 Corvette LS1 vs. LS6?

Hi everyone. I'm a long time member here but haven't had the opportunity of LSx ownership. That said, I've always been a fan of Corvettes. Lately I've been considering a C5 or possibly a C6. I'm not a wealthy guy so I've been leaning more towards a nice 2002-04 C5 and then upgrading as money and time allows. I'm not looking to build a track car or getting into competition drag racing. Rather just a reliable street cruiser with a little extra grunt and a nice choppy cam, nothing too crazy, say 400 horsepower at the crank. I think mimicking LS6 performance in a Targa or Convertible C5 would be a fun build, and likely the goal.

Anyway, I was just looking at a Super Chevy article about the LS history from LS1 through LS9 engines.

Here is a quote from the article: "Around 2002, some of the LS1 engines started receiving the improved LS6 parts such as the intake manifold, heads, and stronger block."

So here's my noob question: Besides a camshaft, what differences are there between a 2002-04 Corvette LS1 and LS6 engine? What parts or tuning did GM use to net the advertised 405 horsepower of the LS6?

Thanks!