Here is your answer
You are confused right ? you just want the cellphone for gps right ?
See
5230
5233
5530
5800
all music series cellphones right so you must not worry about the music and entertainment department
now
camera
5230 has got 2mp and its quality is nice and price tag too
5530 3mp quality is grainy but nice cant say totally rubish same for 5800
now come to the connectivity
5230 no wlan
5530 and 5800 have wlan in there stomach
Screens
5230 means 3.2inches resistive screen and 5233 as well and 5800 too even they are similar in shape
5530 has 2,9inches screen but bright one i also found that 5530 screen response is better when i upgraded the firmware to the latest one on 5530 and 5800 but 5530 is musch responsive
comming to your point
GPS: they all run symbian 5th edition so the software are same ,, you will get charge by the network for using internet according to the package u have
you can have google maps , ovi maps , and all navigation softwares available route66 , tom tom navigation bla bla
My recommendation 5530xm increase your budget little bit more