AAA POIs upgrade in 4050 to 4250

Hi,

I am pretty new to Magellan GPS, got 4050.

Just noticed that 4050 has 4.5M POIs and 4250 has 6M.
Is it possible to download 4250 POI set to 4050 unit or
would it cause problem ?

The reason I am asking is because I previously had 4000 [1.3M],
downloaded the POIs for 4040 by mistake and it worked great.

Also have anybody tried to download Magellan topographic maps to
4050 ?
I often go hiking to remote areas and think it would be very useful
for me.
Would it cause problems with driving maps?

Please advise.

TIA,
Oleg.