Just sharing my experience with remittance and exchange rate;
I have been remitting through Dollardex at Jurong Point to my Malaysian Bank account.
As we are non-Malaysian, the max amount that I can remit is M$9,990 daily. But you can go around by having a few accounts, ie. 4 account x4 times. If not, you can buy in one go M$9,990 x 4 or 5 and Dollardex will remit from Monday to Thursday/Friday depending when you do the remittance.
A friend who bought a properties (bangalow under phase 2) from the developer remit directly quite a large sum to UEM account which is hassles free, just ensure that all documentation all in order and the developer is trustworthy.
Remitting money to Malaysian account is better as the rate given is higher than money exchanger and also changing at Malaysian side.
Maybank account is good to do internet banking to Malaysian entities but their ATM is not that convenient as compared to CIMB.
My housing loan is with UOB because they give me good rates, no lock-in period and no personal insurance cover is needed unlike Maybank.
Try not to carry too much cash as you never knows who is watching, even the locals are wary of handling too much cash in public due to poor security.
Carrying cash over certain amount needs custom declaration due to Bank Negara's requirement and is quite lechay.
With CIMB bank, if your account is above a certain sum which is not really a lot, you can premium service such as need not queue behind most of those doing ordinary banking.
Daily withdrawal is M$1,500 x 2, ie. M$3,000 max daily. You can also top up your touch n go toll card at their ATM (only those with Touch n go sticker).