Hi Guys,

I bought a Insignia Nav01 GPS which has WinCE 5.0 OS, i totally hate the stock one which came with it. So is it possible that i can load TomTom Navcore onto it and run the maps.
I am new to GPS hacking, please point me in the right direction ..

If Tomtom does not work any other's like Garmin or Primo works too.

Thanks in advance.

Well, it kinda depends how that system presents a menu for starting the Nav program--this will define how easy it is to do.
Tom-Tom will be quite a chore (someone else may come along if that is your choice (and they may try to talk you out of it.
Whatever the Nav program that is built in is, already uses Navteq Maps, so if you like those maps, iGo8x and Primo both can use them (assuming they have not been 'customized' somehow) and either would be moderately easy to set up and configure. There are threads on "unlocking" units to run other software--search for these.
Here is a good one:
http://www.navitotal.com/forums/showthread.php?5221-Universal-Shell-V1.0&highlight=universal+shell

I could not find on the Insignia site how much actual program memory that unit has--this may affect how any other Nav program may run (or not).

Thanks after going over bunch of posts I am planning to do miopocket and primo. Are they good choices?

Before you consider Miopocket make sure to check if your device is 100% supported! Miopocket is well known to turn unsupported devices into bricks.
If you only need one GPS software it might be the easiest way to simply put a mortscript into the folder of the original program that starts Primo instead.