Here's what I've found in a TON of research today on coils, I keep coming back to the Delco D585 - the Yukon LS2 coils WITH the heatsink. If it doesn't have the heat sink it's the D514A and should be tossed because of dwell time/saturation/auto-release crap. The other option is the D510C from the latest gen LS7 engines. I'm waiting on clarification on differences between the D510C and the D585 before I make an order.
Here's what I found.
If it ain't Delco/Denso, it's crap knockoffs - garbage.
The LSX guys don't like the MSD coils. They have longevity problems with them. They MAY be overdwelling them though, because they can. Afterall, MSD is short for My Spark Died. My guy was running 1000+hp methanol rotaries and it was the Multiple Spark that killed it. Swapped to a standard D580 (LS1 coil) and the problem was gone. Why, I dunno, just passing on information. Most of the dyno queens around here don't like them either, Dave hates them.
The FI LSX guys are using the D585 and making HUGE power with them.
My Motec guy just engine dyno'ed something like 850BHP on a frankenstiened N/A LSX motor using the D510C's. Those are the ones he rec'd to me before I told him about the D585's. He had indicated that the D510C's are a little more effiecient. I gave him some numbers on the D585's, and he's going to compare them to what he knows about the D510C's and we'll make a decision on what is the best coil to use. Anything above these coils and you're into CDI territory and that's something completely different..... and that I'm ot going to go through becuase of my harness. Honestly I wold like to see 0 gain on the dyno switching coils. If I pick up 20ft/lbs of torque, I'll be doing an M&W on the FD.
Some guy over on LS1Tech took his LS1 F-body to the dyno, ran it with LS1 coils, while the car was strapped down swapped to some D585 Coils and used LS7 wires and picked up 9hp and 18 ft/lbs
That's pretty impressive from a coil on an N/A engine.