Help on Longhorn deluxe modifications

I purchased a Longhorn deluxe from academy about 2 weeks ago and i have used it 3 time. I noticed the temp was 100 degrees different from firebox side to smoke stack. I know i see smoke coming out the doors and there is a big gap where the smoke stake goes in the smoker. Has anyone made mods to this smoker. I think there should be a way to seal the doors and stack. But How do i trasfer the heat evenly. ON the 4th I made 10 slabs of ribs and they cameout great. just need to tweek it alittle.