I swapped to the Bosch Platinum Fours about a year ago and have been very happy with them. I did notice a slight increase in temperature. My ML430 used to run right at 80 C after fully warming up........now she's just a tad above the 80 mark, say about 85 C after warm up.

Gas mileage did increase after the swap, but not sure if I can attribute that to the Bosch's or just new plugs. 80% of my driving is interstate and I average 20 MPG......not bad at all for a big heavy V8 ..........I also generally burn 89 octane with a shot of 92 every now and then....