I've never posted on this forum before, but this is where I got the information about using synthetic urine before I tried it, so I feel obligated to post my results here. I made a mistake which nearly made me fail the test, so I really wanted to share my experience so others can avoid my mistake.
I activated the heat pad an hour before the test, like instructed. The temp strip was at 98 when I left my house. The drive took about 5 mins and once I arrived there was about a 20 minute wait before I was tested. Foolishly, I assumed the temp was still at 98, especially since the instructions assured me that there was no risk of over heating, and said that the pack maintained a steady temp for 8 hours. So I took the test without thinking about it and went on my way. When I got to my car I went to take the belt off and to my horror the temp strip read 104 !!!!! I was sick. Thank god I was instantly relieved the moment I looked at the paper work I had just recieved and on the question: Was the urine between 90 and 100 degrees? it said YES. I thought about and I remember the lady seemed to just take the pee, slap a label on it, and through it in a bag. Im nearly positive she didn't check the temperature. Im assuming she just felt that it was warm so she didn't bother looking at the temp. I don't know how it happened but the temp was marked good and I ended up passing!!

If I had just checked the temp as I was taking the test I could have just blown on the pee a little and brought it back down to temp, but sometimes Im an idiot. Hope this helps someone. Thanks to everyone whos posts help me decide to try the synthetic!