you don't need a valid driving license to own a car be it in SG or MY.
I bought a car in SG before I even converted my driving license, pretty sure the same applies to MY.

When you get the salinan lesen memandu from JPJ you have to fill up a form, if you state that you need the salinan to get SG driving license then the moment you exit MY customs your MY driving license will be blacklisted. Blacklisted is not the same as "giving up/surrender", but I know some folks manage to retain their MY driving license in active state after getting their SG license ($$ only ma, Msia truly Asia )

If you are still young and plan to stay in SG for years, just get your SG license and let JPJ blacklist your MY license. SG license is so much better you can drive overseas without getting any letters from JPJ (most countries they allow you to drive as long as your driving license is in English), no expiry date, and you can drive freely in MY.

Encountered roadblocks a few times in KL, show them my MY IC with SG driving license never got any issues. Once or twice kana a few hungry ones trying to be smart say I cannot drive with SG license I just tell them to check AKTA 333 and they let me go.

Like everyone has replied, you DON'T NEED to own a driving license to buy a car. And certainly you don't need to own a driving license to pay your road tax/auto insurance.

on weekends take bus 170 from Kranji MRT to Larkin, buy your tickets to and fro KL.

Instead of the usual SG->KL, KL->SG trip, you will be doing
SG->Larkin->KL, KL->Larkin->SG. A little tedious but you save 50% of your bus tickets this way, and pretty sure they still have tickets.

Try to get a unit close to Boon Lay MRT so that you can shop/dine/entertainment and at the same time easy to travel to town etc.
If you want even cheaper, find a room near Pioneer MRT. You can travel to Jurong Point via MRT... only 1 station away.

Don't look at just rates alone. Check Google Maps or go down personally to check the location.
I stayed at Pioneer for 5 years, just moved out last month. From my experience... room within 5 mins walking distance from Pioneer MRT is around $500-600 w/ air-con. But at Boon Lay it is $600-700.

Personally I prefer Pioneer as:
1. I usually get a seat when I go to work. Pioneer is 2nd station from Joo Koon. Boarding at Boon Lay, not a chance man.
2. Less crowded at Pioneer.

I have been doing daily commute from JB to SG every workday (via Tuas 2nd link).
Working hours 9am-6pm, but I leave home at 5:30am. Most of the time I reach my office at Commonwealth around 6:30-7:00am.
Tried leaving home at 6:00am (30 mins later) but end up spending more time in the jam.

Going back to JB after work has always been a problem for us. Sometimes it can jam for 1-2 hours even if I go back at 8pm.

Driving bro. Coming to work jam is pretty OK; reach MY kastam 6:00am usually clear SG side around 6:30am.
Going back from work usually stuck immediately after Tuas flyover underpass. Sometimes end up jam 1 hour crawling to SG kastam.