If making phone calls and the odd bit of texting is all you are wanting the phone for then get something like a K800i and stick the rest of the cash in your pocket.
You'll be able to buy a dedicated sat nav unit and still have change as well.
Never had a problem here with the speaker volume?
Well, its not a major problem for me, I dont notice it in everyday use. I have some videos at home that i encoded for my old M3100, i will stick one on the tytnII and see how it performs.