i'll tell you my experience
I overhauled my mothers Honda Accord engine somewhere in early 2000 - and installed bosch 4 tip platinum plugs - drove the engine for 120,000 kms without a misfire - with original engine performance (no enhancement) at that time I removed to inspect them and for fun installed new BKR6EY11 plugs that the engine originally should have, same performance with no change at all.
drove it around for about 25,000 kms like that - still no feeling of power reduction or anything - removed, cleaned and regapped, good performance - removed again at 50,000 kms upon which one plugs ceramic was damaged on removal. Put them aside and ripped open the new NGK platinum box I had - installed those - same performance as copper plugs - no different - funny part is that those plugs have seen 250,000 kms of driving now and the engine is still perfect with solid compression and no oil consumption.
I must add that the ignition cables being used are 6.6 kohms NGK plug wires that I bought in the year 2000 - now their resistance is about 8 kohms
the bosch units I removed were used in a MB engine for about 80,000 kms - one plug was lost during maintenance - then the rest 3 are still in service in a Charade engine
result - multi tip will not increase hp
precious metals will not increase hp - they just are very long life compared to regular copper plugs