http://www.318ti.org/forum/showthread.php?t=15863 Every type of plug has proponents and critics.
Bottom line: nobody seems to have had any problems with the OE NGK plugs(BKR6EK), and they are available for $3.99 @Pep Boys.
I'd go with a fancier plug that cost twice as much only if I were
certain that it was going to last twice as long. Hopefully, it would work as well as the stock plug, but with all the different reports, who knows.