I'm running the stock BMW 5k caps and Bosch WR7DC (remember, I've got the post '85 unleaded model).
I'm using them 'cos I bought 2 x 6 packs at a really cheap clearance price from an auto parts shop that was closing down years ago, and I now have plugs to last me years.
My reasoning was thus, an extra 5k resistance, in a circuit that already has an infinite resistance gap at the plug, is negligible. When the plug gap arcs, the arc is considered a conductor so has its own resistance, and at the voltages impressed on that circuit, these resistances totaled are not insignificant though for all intents can be ignored and help with current limiting to reduce spiking which causes EMR (RF interference).
Also, my car (an '87 Toyota Corolla) specifies resistor plugs as well as suppressor leads. These leads vary from 12k ohm from the longest lead, to 6k ohm for the shortest, and add to this the coil to distributor leads resistance of 12k ohm, can add up to a maximum circuit resistance of 29k ohm!!! My car has run to 250000km without any problems so far, and still on the original coil.
Try the NGK Iridiums.....................be bold and adventurous!!!!