I just put autolite 25s ($1.64 each) gapped at .054 in my 94 GT last week and they solved my missing problem. I've read that some people have had good luck gapping at .045-.050, but I just stuck with the Ford specs for now. I had NGK UR45s for the last 2 years and ~9000 miles. I don't know what happen to the NGKs because they all visually checked out but for less than $15 I took a chance and just replaced them. I'm going to guess that somehow one of the NGKs grounded out or the insulation cracked and I just couldn't see it. Either way, I searched a while trying to find a good plug, just as your are, and I found that most people leaned toward Autolites 25s in a 5.0 GT. I only have 150 miles on them but no complaints either.
1994 Mustang GT Convertible. - YMR# 8045
Moates QH & BE/EA, J4J1/CBAZA, LC-1, 306, GT40s, TFS1, SVO Intake, #24s, MAC headers/catback, Bassani X, MM CC plates+springs+SFCs+LCAs, K&N, KYB shocks+struts+quads, MGW shifter, tires:245 F/275 R, 3.55 gears, FRPP Alum DS, Centerforce DF
Last edited by Ryno8705; 10-27-2008 at 08:58 PM.