Personally I would NOT recommend monster performance for suspension, I was completely unimpressed by Ian and his work and all my shocks after I got them back from him.
if you say money isn’t an issue, I would go with Teixeira LT maximum ground clearance arms with Motowoz shocks. this is going to be more than what you need, but having a stronger arm with more ground clearance and a nice shock built for you is going to make the front and feel a lot better on the trails. The rear suspension should just need a re-valve and a respring with a different XC shock linkage and you should be good to go.
For trail riding I really like Hiper wheels. I have smashed my wheels on so many rocks at high-speed on the trails and blown tires and the wheels won’t bend and if you do get a flat the beadlocks will keep the tire on until you make it either back to camp or somewhere that you can fix your tire. then find a good set a tires that you like. For me, 22 inch tires are too tall in the rear, but depending on the trails you ride that might be better. I ran ITP Holeshot HD tires for quite a while and they were the gnarliest tires for really rocky jagged trails. Otherwise ITP GNCC tires work great both front and rear for fast trails that aren’t super crazy rocky.
once you get your tires dialed in, then you can mess with your gearing a little bit if you feel you need more low-end pull to come out of the corners faster. I like RK EXW chains and Supersprox and Dirt Tricks sprockets.
As far as the motor, that really depends on what you feel you need. Many times a stock motor is more than enough on tight technical trails. But some trails will open up quite a bit and you want more power. As mentioned, stage two cam will make more power, but that’s going to be more top and oriented, especially on your year of quad. There are a lot better cams from WebCams that would work for your application. As far as losing power and throttle response by removing the airbox lid that is not the case. You will not lose throttle response by removing your airbox lid. It will be louder and you will have to reject for it though.
what it all comes down to is building a quad isn’t just a matter of throwing the best parts at it and making it awesome. You need to think about what you want to be better, or what doesn’t work well for you. Personally I like my handlebars taller so a +2 steering stem is important to me. Some guys really want Nerf bars because it’s muddy and their feet slip off the pegs a lot. Some guys ride Rocky and rutted trails and are sliding over a lot of obstacles, and so for them a nice poly skid plate is a must. Others ride at night a lot, so good set of LED lights is important. Think about what you want to change next time you ride and then work on that aspect of it until you get it dialed in. That’s the fun of building a quad.