My GPS app actually states this lap was 1:30.59, yours shows 1:31:00. Sounds petty but this would move me up a position.
I initially left segment times rounded to full seconds because regular phone GPS signal is not very precise (usually 1 Hz). Since you asked, I changed it so that track segments have precision of 0.1 second. Now you have 1:30.5. The 0.09 difference between your GPS app is probably due to the fact that I didn't exactly match the start and finish points when I created the track segment.
At 1:31, I believe I would also hold 4-door sedan record?
Correct. There was a bug where GPS lap times were ignored for track record listings.
Is there anyway to change my user name on my profile? I used my brothers FB to log in so its shows the incorrect name?
I added "full name" field in user profile https://fastestlaps.com/usercp. Whatever you enter there will show up in track pages, instead of your username. Just note that changes won't appear immediately (may take up to 24 hours).