Shane, couldn't you get the Tri-Y? I'm running my Tri-Y's  with the original cat, 2" pipe and a single Turbo muffler in front of the diff. Noise is fine, response is a little better and a bit more go throughout the range. Not startling but good.
CJ,
I ordered them with out seeing them and though they would be tri-y too. The stock system is 4 into 1 and Calmini header is 4 into 1 so may be theres a reason for it
I'll give em a go seems they were cheap anyway
I solved a long time problem tonight that has been bugging me for near on a year now. I've had sh!t acceleration after 2750 Rpm and even revving the engine on the spot it dies off after 2750ish. Power has been dramatically down and I was struggling to keep ahead of my mates sj413 (on the road) with a 1300 in it the other week end.
I compression tested it last night just for piece of mind and got:
#1 |removethispart|@190psi
#2 |removethispart|@195psi
#3 |removethispart|@190psi
#4 |removethispart|@200psi
So no obvious problem with compression, then this afternoon I when about fitting the header and new fuel filter, plugs, ignition leads, Dizzy cap and rotor thats when I noticed the earth off the dizzy to the fire wall was not connected !!!!!\
Connected it back up and whooa what a difference !!!
Starts better, Idles better, freely revs on the spot right round to 6 grand no problem !! I think I've solved my problem
I can wait to finish the exhaust and road test it.
Can't fricken believe a little wire has caused some much power loss thou