Frankly, I believe that you will be served just fine with just about any of those plugs. I do know that many here have had some issues with Bosch Platinums, but I'm not 100% sure that this applies to the NA L36. For example, my car ran just fine from 2003 until just last October (2006) on a set of Bosch platinums that were installed by the dealership when they did my UIM and LIM gasket replacement. It ran smooth as butter with no spark issues ever.
They all looked clean and fine when removed.
Those were replaced with NGK copper at that time. Not because there was a problem as much as we were in there at the time and it was a good time to replace plugs too.
But in the end, the NGK or Autolite coppers are probably the least expensive out there and work fine.
Mike: 1997 SE w/ 183K, aka White Horse
, Gutted Airbox w/K&N, drilled 180* t-stat, tint all around, clear corners w/SilverStars, "PONTIAC" light up tail, PEMs, NGK TR55s