Also what would be my HP increase with/without tune. Lastly what would be my HP with prefab tune vs. custom dyno tune. I have AEM Intake and Magnaflow exhaust.

TIA,
Mat

 

Well yes assuming you use the colder plugs as well.

 

What about HP differences? Stock vs. Tune vs. Dyno tune?

I've got K&N Intake and Magnaflow Exhaust.

 

Well a pulley is going to gain you approx 15-20hp. The car will run if you only do the pulley and belt, but you really need to do the colder heat range plugs too We find cracks in the cylinder head around the plugs when people keep the stock plugs and up the boost. Expensive repair vs cheap plugs. Check out our kit is has everything you need
WMW pulley kit

 

^^ +1^^

 

Just another reason to let the engine breathe better before you going adding 50% more boost. Stuffing that much more air in an otherwise restricted motor isn't a great idea.

 

I just had a new supercharger, water pump, 17% pulley, 380 injectors, belt and colder plugs installed on my 04 JCW on Monday. My car runs better and smother. It did gain some horsepower but I can tell it would run much stronger with a tune. I lost a lot of my pop and burble but I think I will get it back with a tune. The only other engine mods I have are an Alta "CAI" and a resonator delete on the JCW exhaust.