The AA5 has a tank selector and two tanks to think about for a start. It may not sound like a big deal but in a 152 you total the two gauges - in the AA5 you only use the one selected. There may be fuel in the tanks but its useless if the empty one is selected. This happens quite often when people convert.
The handling with 4 up is also a bit different than a fully loaded 152. If my memory serves correctly, the CG and Weight & Balance needs watching too.
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TwinComm