I just got a set of 4 Bosch Super 4. Yes, its true that plug is the one with 4 legs. Cost me 20 bucks per plug but so far after using it, no major difference in terms of performance. But i'm more keen to see if my fuel consumption improves. Plugs in general don't give much of a performance difference but it burns efficiently thats all.
I was so tempted to try the Denso Iridium. Price was RM200 for a set of 4 and i think twice and reasoned out that my car isn't that highly tune or turbo and don't require such a high grade plugs. Maybe when i go turbo, i'll use them.
BTW, there's one guy in the 'Engine and Performance' section of the buy/sell thread and he's selling some pretty cheap performance plugs. Just found out that the same Denso Iridum plugs that was retailing at RM200/set is just selling for RM168/set. Worth a try if you have the budget.