Any problem using iridium plugs? Napa gave me NGK, BKR6EIX

Good plugs, I use them in my Turbo Tracker. Shouldn't be any issues as long as they're the correct heat range and depth. You'll have to look up the number to be sure. I'lll check the box I have for #'s tomorrow.

I used iridium plugs in one of my previous Trackers.  There wasn't a whole lot of difference, I noticed a slight drop in fuel mileage when I switched from copper to iridium, 5 or so miles less per tank on average. 

On other vehicles I've owned, switching from platinum or iridium plugs (installed by POs) back to copper plugs has made slight seat-of-the-pants improvements in throttle response and power.  These, however, were much higher-performance cars - one with a high-compression V6 and a 100hp nitrous oxide system, the other with a tuned-up V8.  I never did any kind of objective testing, though, so take that for what it's worth. 

In a tracker/sidekick/samurai, I don't think that the plug type is going to matter all that much.  Iridium and platinum plugs last quite a bit longer than copper plugs do, so that cuts down on the regular maintenance you'll have to do. 

Iridium and platinum plugs last quite a bit longer than copper plugs do, so that cuts down on the regular maintenance you'll have to do. 

I agree........ even with no real performance gain, the fact they
run a long time is the reason I think they are worth the extra few
$$.

Not all iridium plugs are created equal(the price usually dictates the quality) and in most circumstances with the suzuki 1.3/1.6 liter engines they are unwarranted and a waste of money compared to the cheaper platinums. Where the Iridiums really shine are in modern engine applications where combustion pressures and temps are rather high(for emissions, performance and mileage) and a longer life plug desired, or you have added forced induction.
I have used copper plugs in every engine that I have owned that were designed with Iridium plugs in mind(NA and FI), they perform as well if not better than the Iridiums when brand spanking new, but erode very quickly, usually in well under 2000 miles.
Also the stock replacement plug wires will degrade enough to impact performance in as little as 10K miles.