for the front i found that adding an extra 20-25mm of fork oil stiffened em up just the right ammount for my 165lbs.
Despite what anyone else may say, I have used fork oil level to fine tune the fork spring rate. Remember PV=nRT, part of the Ideal Gas Law, which gives the pressure increase of a gas in a variable volume container. At the stock height setting the air spring value adds 27 pounds (gauge) to the spring rate at full stroke. Adding one inch to the oil height bumps this value to 32.3 pounds, and adding two inches takes it to 40.2 pounds. As gas pressure rise is exponential the greatest effect is near the end of the stroke.
There is a downside to this -- as the air pressure rises the fork seal lips have considerably more pressure against them, causing inconsistent fork action through the last 1/3 of the stroke due to increased seal lip pressure against the stantion tube surface (friction). It can have a significant effect on compliance if you go overboard with this.
There is a way to increase the rate of a spring: shorten it and add a longer spacer to compensate. Removing coils increases the rate by simply increasing the load on each coil remaining. It must be done properly by creating a new "dead" (shorted) coil at the cut end and grinding it absolutely flat, otherwise the spring will bend as it compresses. Also, be careful when doing this as removing too many coils can cause the spring to coil bind before topping out, sending loads on the fork cap and upper surface of the damper through the roof, usually breaking something.
There are physical limits built into any fork assembly which define the travel available, and unless you grossly overfill the forks the travel limitation stays with the hard parts. Damping rates, however, do not significantly change with pressure in the system -- oil moves through an orifice at a relatively fixed rate regardless of the pressure, and as long as the entire damper is immersed in oil at full extension the damping rate will not change over the full stroke. One variable introduced is while the damping rates do not change with pressure raising the oil level increases the effective spring rate, so some tweaking of the dampers will be necessary to compensate for this.
My recommendation? As several have already said set your sag properly, then fiddle with the damper adjustments until it feels right. Past that you're talking $919 plus shipping for a better rear shock (I don't remember where I heard that), proper springs for both ends, and a lot of time and meticulous note taking getting it all dialed in properly.