Does anyone have experience with upgrading the supercharger pulley as well as the air intake for the 3.8 liter Bonneville(3800)? I am just wondering if the money will show a significant difference in power, mpg etc. Apparently there are about 7 different aftermarket pulleys and I wouldn't even have a clue which size to get. Thanks.

Yes, I do. I suggest nothing smaller then a 3.5" unless your going to do more mods. You may see about 15 more HP or so.

Is that 15 hp from both the cold air and smaller pulley? Or just 15 for the pulley?

The intake really wont give you any more HP, just give back what is lost from restricted air flow. A 3.5" will give you about 2 more PSI of boost at WOT. Much more then that and you will need to open up other areas like valves and exhaust. Boost is not power, flow is. Once you reach the max flow rate it backs up and builds pressure causing more heat which causes knock retard, and that pulls timing, as well as makes your engine go boom.

Tks Dan, I will keep this in mind. I was just looking for a little bit more performance and possibly a little better fuel economy and these 2 were relatively inexpensive. I'm not really looking to open up the exhaust, as that will probably be too much $$$.