Check the shrader valves. I had my low side leaking and had to replace it.

The Evap coil is crammed in the dash, just follow where the hard lines pop up near the brake booster and there you are.

If you are going to go through the hassle of replacing that, then I'd do all new lines from the compressor back, new accumulator/drier, condenser and orifice tube so you know everything is good. I went through this on my 00 GT and it ended up just being a clogged orifice tube, which sucks since you have to remove the ABS/master and brake booster off the firewall to get to the stupid thing, lol..

Thought mine was always low too but what was really going on is when it would get warm, I'd top it off. Little by little this overcharge the system, which even if the orifice tube wasn't clogged it would have the same effect. Once the blockage was removed and I refilled it with the proper charge it's cold again.

And yea, I hate A/C issues. With a passion.