My 2nd gen '03 has the same type of vents that have cracked (both front and rear) and the front one actually leaks raw gas when the tank is more than 2/3 full while parked on a slope. I have removed the tank and found the manufacturer's name Eaton molded into them. After researching, I concluded they were made of HDPE, high density polyethylene, which is difficult to impossible to bond. I bought a low cost hot air plastic welder from Harbor Freight, and a few different shapes of HDPE welding rod from various online sources to practice with. After completely draining the tank and blowing compressor air into it for a few days until gas vapors were gone, I have now welded the cracks. I believe the welds were successful, but I have not yet pressure tested to verify. This is a casual project, so I won't know for a while until I finish the job. but I thought I'd post it for consideration of an alternative process. I'm taking photos as I go, and if eventually successful I will post results. Be careful the welds don't interfere with the quick connect vent line fittings. Just be extra careful that there are no fumes present. Even though I felt it was safe I had a fan blowing the area and a fire extinguisher handy.