[Z U L8R]

sounds about right.

if you can get her back on the dyno and lean out anything below 11.5 a/f's and it still blowing out spark with close to stock ignition timing on your timing map then there's really nothing else it can be other than a bad ground (which you've fixed), a cracked plug (which you've changed), or a bad coil pack arching out under load.

so between tweaking the tune a tad bit or getting coil packs, sounds like the problem lies therein at this point. you've pretty much done everything else you can do.

if your air/fuels never drop below 11 and pretty much stay in the mid 11's where it's breaking up then i wouldn't mess with the tune till you got some different coil packs since all the basic easy stuff's pretty much been covered.

the only other thing i'd analyze/log before i get all crazy would be your charging system.

basically so you can make sure your fuel pump/ecu/coil's and everything else isn't losing juice at high rpm's causing this issue.....

coil on plug is more desirable but some alternatives could be lsx coils, and/or grand national coils, not the brick of 6 which will work but look tacky, but like the msd ones that electromotive uses, you can get 2 from summit for like 50bucks each, then some 8.5mm msd wires, you'd probably be in it less than $200.......

just throwing some ideas out there, best of luck man

Dave