I've just started using Pre-MIX in my 13B-MSP. Smoother feel almost immediate after the 1st fill-up. I'm putting in bout 200ml (believe it's a US quart) for every 50 litre tank.
Like lennon said RM 60 for a 1 litre bottle to last 5 fill-ups.
Im new here, but haven been driving/owned MRS since last 4 years in Miri. Just recently transported back this car back to KL. I think my SMT is about to die, hence im thinking of...