Check O2 sensors.

I don't own a Preve 

Of course there is a difference between turbo and non-turbo, not just performance but also safety kit. As for reliability, the CFE engine is only about 2 years old, most users don't have any major reliability issues yet....but it boils down to your luck.

For the price (RM69k with current discount), you get a lot of value compare to other brands on the market. But you just have to live with Proton's QC lah.....gain some lose some.

Preve Turbo is value for money. Personally I recommend the Preve Turbo over the low-spec version as there are not only more added features in the GPS touchscreen and paddle shifters but the added power in acceleration will be useful for drivability. Once you've got used to a sufficiently powerful car, it will be difficult to drive an "underpowered" car. The only downside is the slightly loud Turbo engine but it's still manageable if you keep the speeds below 120km/h and don't do any hard acceleration too much.

Reliability of the Turbo engine may not be as good as the normal version. However, I feel reliability may be more to the way you drive. If one always drive fast and furious and always do hard acceleration with rpms reaching 4000 or higher, chances are the gearbox or engine may break down quicker than you expect. If driving normally, I suspect the Turbo engine will still reliable with many years to come. Personally I think the gearbox transmission may be more prone to breaking down than the Turbo engine. The rougher you treat the gearbox(frequent hard acceleration), the quicker it will be damaged.