Headers...which one to choose?

Your OEM headers cracked because they are 4 tubes welded to a pressed-steel stamping. The stamping expands more than the tubes & their welds can withstand, so the rarest thing in the future will be an un-cracked set of stock headers! All other headers are made entirely of tubing and do not crack. Hall & PI headers are both quite good; be sure their flanges will accept your stock mufflers, unless you mean to replace the entire exhaust system. There is little to choose between the two as far as performance is concerned, unless you also replace the mufflers. In exhausts generally, as noise gets louder, performance goes up, so you may want to consider the sound, too.

Be advised that Hall sells several different styles of header, each with strengths and weaknesses.

The ones he's known for are his "Big Bore" exhausts. I personally can't stand the tailpipes, but the headers are quite good, with the caveat that the collector is very restrictive. They are designed to bolt right up to stock-diameter tailipipes, which necessitates the small-diameter collector.

He also sells locally produced copies of the factory GTS headers. These are large-tube headers with a larger collector; they will NOT bolt up to stock tailpipes without modification (although the work to whack off the first few inches of the stock tailpipes and weld on a neck-down collar would be simple for any muffler shop.)

The individual tubes are probably TOO big for max efficiency at street RPM, but they are still a nice option. As an added bonus, he's currently selling a complete system (headers and factory GTS tailpipes) for about $1300; the headers are coated, too. I have that complete system on my car and love it.

Larry Stock sells Hedmann Headers, which are a true 4-into-1 design (the GTS headers are 4-into-2-into-1, tri-Y, sort of.) I've heard they are actually sized for 2v ports, which he denies. But he does state that the port size on the header flange is smaller than the 4v exhaust port, which would lead to turbulence IMHO. Highly recommended for 2v heads though.