I've heard the Mac longtubes will work. The key is the primary needs to extend out a couple inches before turning towards the collector on the drivers side, passenger side is usually not a problem because the plug is slightly in front of the primary tube which angles back away from the plug.
If anyone is adventerous enough to modify their headers heres how I made mine work. I'm using Hooker Competition headers, 1 5/8 primaries.
The passenger side fits no problems, have to use 90 degree plug boots but thats it.
The drivers side needs modifications. If you're handy with a sawzall and a 4" grinder and a welder you can make it work pretty easily. Basically each tube needs to be extended out away from the mounting flange about 1" + before turning towards the collector.
Check your clearance between the shock tower and the headers, get three 1 5/8" U bends from Summit or Jegs.
I did all my cuts and welds with the heads on the work bench and the headers bolted on, wouldn't even attempt it without doing it that way. And finish cutting and welding each pipe before starting in on the next one.
What I did was cut each primary about 1/2" away from the flange.
Then at the next downstream bend in that tube, towards the collector usually about a foot away, heat the pipe up and bend it away from the flange about 1". Now you've got a 1" gap where you cut the pipe from the flange.
Depending on how well the pipes end up lining up you can either fill the gap with a straight piece of pipe, or remove more of the primary pipe and use some of the bend in the new U bend pipe.
I'm not a very good welder, but with an acetylene torch it worked out pretty easily. Definitely worth spending more time getting the pipes to butt together good then weld, thats where the grinder comes in.
I didn't try this with a brand new set of headers either, picked up a used set of Hookers for a little under $100.