[s-cars] URS4/S6 alternative Spark Plug options?

[keithbedard at verizon.net]

Just wondering if there are cheaper spark plug options than the Bosch Platin F5DPOR.  I was looking on summitracing.com, and they have some models (such as NGK 6097) that claim to work for these cars, but I am very wary to put such a cheap part that I have heard nobody talk about into such a great high-perf engine.  My ECU is chipped, which makes me more cautious.  Sorry to be cheap, but the cost of those Bosch plugs always makes me wonder if there are other options for URS4/S6 with chipped ECU...  Any experience/suggestions is appreciated.  Thanks.