Improving Compression In Your Engine

I notice that on certain days my car feels like it has more power and runs smoother...

The upgrades that I currently have are...

Magnaflow Catback
Injen Cold-Air Intake
NGK Iridium IX
Magnecor KV 85 Ignition Wires
9 Lbs Superlight Race Wheel 17"
Royal Purple Racing 21 Oil
Royal Purple Max ATF Transmission Fluid
Falken Azenis St-115 17" Tires
Brembo Slotted + Crossdrilled Rotors

And the car is a 2000 Eclipse GS with about 76,000 miles on it.

I know on a cold night where the temperature is about 55 Degrees Farenheit the engine runs alot easier and the throtle is alot more responsive because engines run alot better on colder temperatures...

My question is... how does the temperature in an engine affect the compression in an engine if any?

Also if an engine has lost some compression what is the best way to restore it if not improve it beyond normal?

Would a higher compression affect MPG?

Basically I want to improve my compression! I want my engine to perform at it's best and run like new if not better. How can I do that?

Thanks...

-Nexagen

I have a link about restoring lost compression in my restore thread the thing is im not sure if it truly works however some one said it did check it out

Cooler air is more dense, and produces more power. Denser air has more oxygen in it. A modern fuel injected car will automatically compensate and deliver a bit more fuel. The rule of thumb is a 10 deg. F drop in intake air temp gives you 3% more power.
This is why its important to have a cold air intake system on your car.
As for compression and MPG. Higher compression gives you better MPG and better power, so long as it does not detonate or 'ping'.
A higher compression engine has greater thermodynamic efficiency. It gets more energy per gallon of fuel.
This is one reason why diesel engines get better mileage than gas engines. Diesel fuel can tolerate up to 22:1 compression, for better thermodynamic effieincy. The highest gasoline engine is 12:1, tops, and its rare for a production car to have much more than 10:1.

You may also notice improved performance during periods of high humidity or rain. This is due to the water molecules slowing the combustion process slightly effectively the same as an increase in octane. Drag rasers in the old days would use a "cool can" which was a coffe can with fuel lines coiled inside. You would fill it with ice before your run. And on street racers we used to use water injectors. Not a lot of power but some and the engine stayed very clean inside. My jet aircraft in the Navy used water injection increase thrust during takeoff
Injection of water into the air-compressor inlet increases the thrust, but can be used only at take-off because of the high water consumption.