I'm with lil bastard on this one. I think it's a waste of money.
no one will be able to tell you have "S" brakes on the front anyway...they look very similar to base model brakes..so to me...there is no bling factor.
if the rotors are larger, you're adding more unspring rolling weight to your hubs...theoretically it could make yoru car slower as you have to accelerate the heavier rotors...maybe it's a smalll difference in weight..but why add it if you don't need it.
I have a 2000 base. shortly after I bought it I did new pads, rotors, rebled the s ystem... and WOW. my car stops so fast it's nuts. I can'tq uote 60-0 times, but having driven a lot of cars - the stock brakes on my base boxster are AMAZING. my cars stops on a dime. i have NO desire to modify them.
I did want more bling though, so I spend under $100 and bought a can of high temp brake paint and painted my calipers. took a few hours, and the results look as good as "S" brakes. I did mine in red, and put on PORSCHE decals... it looks OEM.
my vote is to just service your brakes - put on quality pads and change out rotors if they need it - bleed your lines, maybe upgrade yoru brake lines if you want - and then while you have it all apart - paint your calipers. the painted calipers is what really makes teh car stand out!
good luck. use the money you saved toward future: tires, repairs, track days. etc.