Your specific setup is going to be based on how much you weigh. Every bike I set up, I set up differently for that specific rider.
Another tip: If you do a lot of mud riding, DO NOT run shock-wears (Covers). Shock-wears do more damage than good in wet environments. They trap moisture, and inhibit rust and seal rot.
When you are shopping for shocks, avoid triple rate shocks. Banshee's are way too heavy to utilize that third spring, whatsoever. Dual rates are the way to go. You will be wasting money with anything more than a dual rate. If you do a lot of tight trail riding, maybe consider keeping the stock arms, to avoid being too wide for some trails. Stock length swinger, or a +2 will give you additional leverage on your rear shock, and will give a softer, more plush ride.
Again, though, your weight is going to be the primary factory in what setup I would recommend.
For about 80% of people, a set of good, dual rate shocks with reservoirs, and a revalved stock rear is the way to go. If you absolutely must go aftermarket on the rear, at least get an aftermarket shock that has the same adjustability of your stock rear, so you are not downgrading from your stock rear. (Rebound, compression, and threaded preload). That would be something similar to an Elka stage 3, or Works Black Widow. ($800-$900)
As far as the 450 front end goes, I'm pretty sure most people know where I stand on this. I don't recommend it, UNLESS you can get the stuff very very cheap. Less than $300, for everything: Shocks, arms, spindles, tie rods, brakes, and hubs. If you do go the 450 front end route, Expect that your shocks will need to be revalved, and possibly resprung. Dual rate spring kits are around $250.00 for the pair. If you have any other questions, feel free to give me a call, or shoot me an email. All my contact information is below.