I was not exposed much on Mobile Virtual Network Operator (MVNO) like XOX, Tune Talk, REDtone, redONE, Altel, etc. I was on redONE for a while before switching back to Celcom (now CelcomDigi) to be able to subscribe to cheap about RM40 . I'm not using data except for payment like e-wallet. So usage just probably 100MB + per month I guess.

For the GPS I use Maxis one because I only heard about it. Anyway, I think it is good to subscribe to main carrier service instead of MVNO. For me MVNO probably has limited bandwidth allocation from main telco but probably they have less subscribers

The Maxis one is good because you pay RM30 for 1 year validity. The grace period is no less than 1 month I think (forget about it). This is just to keep the number valid for 1 year even if you ran out of data. For data you need to purchase separately which can be
2GB Internet for 365 days at RM6
4GB Internet for 365 days at RM10
10GB Internet for 365 days at RM20

Went to Maxis and you can select which number you like. The initial payment is RM50. I think RM30 validity and the RM20 for data. 10GB? forgot.

I was confused too because so many article like Maxis discontinue but still there. You can go to Maxis and ask.

Port in? Oooo.. I did not port in because I use the car HU that can install SIM card. It is immediate unlike using phone as hotspot. Last time I use device (MiFi) for hotspot but sometime it is just too slow for me

I think it got activated within a day. Go get explanation from salesman.

Yes you port in to keep same number. I just get additional number but the car unit cannot accept call