Yes a colder plug will help some, but if you're lean then that is what your main problem. You being in Alaska you may want to consider tuning software. I don't know about EFI live but with HPtuners it is upgradable to other future vehicles. With the WB it will probably be the best bang for your buck. It does suck haveing to keep swapping out pcms. Did you stick with the whipple electronics/injectors or did you upgrade your injectors along with the pcm tune? A lot of people do away with that piggyback deal.
Dave
2003 Silverado SS here's where my money went...Radix @ 9psi, Vortec IC tank, Oversized Heat exchanger, ASM LT Headers, Suncoast Ram Air hood, Airaid intake, Trailblazer Torque converter, Full billet servos, Zippy kit, cat-free, Flowmaster muffler, Gaylord Speedstur tonneau, 3/4 drop with Belltech spindles and leafs, Sirius conversion & MTX thunderform sub box. 05 e-fans coming soon!