OK, just to get the N/A side going I thought I would add my thoughts on some of my latest mods that relate to power gains.
After spending last summer completely stock as far as the engine is concerned I had to do something. Turbo had to be put on hold for another year so I decided to do CAI, exhaust and tune. Unfortunately they were all installed at the same time so I cannot give details of how each effected the power individually. Installation was easy. The CAI had clear instructions and went together very easily. The hardest part was re-routing the wires for the throttle body and that was quite simple. I would say it took about 30-45 minutes to complete.
The exhaust took a little more time. I installed the exhaust onto the stock manifold first as my header had not arrived yet. Body panel removal was a little time consuming but was easy as I had it off before. Finding all the screws can be a little difficult at first. Once the panel was off, removal of the stock exhaust as a complete unit was a snap. A few springs followed by a few bolts and it was off. Installation of the new exhaust was straight forward thanks to the Alpha instructions. The only problem I had was mounting the tailpipe. That clamp was a bit of trouble by myself but once I had another set of hands it surrendered. Cutting the hole for the plastic is simple. Harbor Freight has a cheap set of hole saws that worked fine. It was under $20. IF anyone is in the central Illinois area and wants to borrow it, give me a shout. Overall, it may have taken about 2 hours but that was with a few breaks to yack with neighbors.
So with the parts installed, off the computer went to get a new flashed with a new tune from Bob at MEFIburn. Sent it out on Saturday, had it back by Thursday. While that was away, my 1320 header showed up. Swapping that out was simple. It only took about 20 minutes. Stock bolts came out easy. I had already purchased a new exhaust to head gasket from O'Reily's I had to loosen one bold where the exhaust bolts to the transmission just to get it to move a little to get the header in. All the bolts went in easily and with no grinding as others have reported. It did take a combination of sockets, extensions and open and boxed end wrenches to get it tightened up. Start in the middle and work your way out to tighten will give you a leak free fit.
The computer came back right as the weather got cold again. So after a brief shake down ride, the Sling went back in the garage. Now that it has warmed up, I have gotten a chance to put some miles on it. Wow. is all I can say. The performance gains are minimal, probably in the neighborhood of 20-25 HP, if that much. But the drive-ability is awesome. The throttle response is right there. The motor didn't have to think "hey, he is hitting the gas now, I guess i better rev up" like the stock tune. Tap it and it responds. And it is still learning! At first it was good, after about 300 miles, it is great. The seat of the pants feel is much better. I told the better half last night that this thing is gonna get me in trouble. It is almost impossible to keep my foot out of it.
So overall, the investment is well worth it to perform these mods. It makes the Slingshot the driving machine that Polaris claims it is. Make no mistake, it won't keep up with a turbo, but it still is a heck of a lot of fun. Thanks much to Henry at Alpha, Josh at Slingmods and Bob at MEFIburn. Enough for now, gotta go ride.