I've spent quite a bit of time on the dyno in varying states of modification and about the most we have been able to make with a chip is about 4hp. For a N/A combination, you're just not going to be able to do much other than fuel enrichment and timing. You can handle both those with a good ignition/distributor and an AFPR. Right now, the only thing my chip is doing is extending the rev limiter to 8000 and shutting off all the annoying emissions functions. Everyone's mileage may vary, so to speak, but my experience has been that there's just not much to be gained. Unless you've got the EEC god himself in Mike Wesley at your disposal, I think the money is better spent elsewhere.
I will say though that there is more potential for the chip to do some good with a late model 4.6 than there is with the 5.0.
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Jeff Chambers
T/S #3
11.462 Seconds/117.43 MPH
Chambers Racing Team