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Forgot to say, good luck with the Warrior - I transitioned to a Cherokee after 10 hours in a 150 and its no problem at all getting used to the extra weight and the different configuration.
If you can, try an Archer at some stage, the 180hp engine is a gem in the airframe.
Perhaps the only three things you really need to learn going to a PA28 from a 150 are:
1 Fuel management - get into the routine of changing tanks every 20 mins or so "fuel puimp on, change tank, check fuel pressure, fuel pump off, check fuel pressure"
2 Be a little sharper on navigation - you'll be cruising a little faster (Warriors do 95-110kts depending on how you set them up and how well the mags are sorted - so you need to think that little bit faster
3 Threshold speed is important... learn the number (usually about 65kias, but POH will confirm) - don't approach too fast, or you will float halfway down the runway! The Warrior wing has very good low speed characteristic.
Also, it likes full flap unless theres a screaming cross wind, as the Piper flaps are not so effective as the excelent flaps on the 150 - don't get me wrong though, it has got to be the easiest plane to land, you have to work hard not to do a greaser most times!
Enjoy!