1. new
2. new car interest rates
3. possibility of cheaper parts since it is proton own R&D car like waja, persona, gen2, etc. inspira parts as expensive as lancer gt.
4. inspira no turbo

I don't really see a point moving from Nissan Latio Sports to Proton Preve unless you have issues with your Latio and want to change to something else of the same class but cheaper. I'd rather either take a not too old used D-segment or better C-segment car, if prefer new then wait until can afford higher priced car to be worth it. Latio to Preve feels like a downgrade.
Depends on what is your requirement.
You like small, unsafe, old, relatively expensive to buy, and cheap to maintain. Its a good buy.
If I were to guess you're looking at the 2005 models they're selling for around 25-30k, that's expensive.

2008 Proton Waja CPS - for that kinda money, its more worth it to get something like this. C-segment - bigger, safer and more spacious. Only 5 years old. Maintenance cheap.
Savvy - personally, I wouldn't touch it with a ten foot pole 

Swift - they just refreshed the car, though it looks like they kept the under-pinnings.

Fiesta - VW's DSG is famous for issues they even made a recall for DSG across all its model range you can read it here. The dual-clutch that's inside all Ford's come from Getrag not too many complain about it as much as VW's DSG. There are a few reasons why its more stable; 1. power - the PowerShift doesn't need to handle a very powerful engine so less stress on it unlike the DSG which has to handle over 200nm of torque. 2. Paddleshifters - for our market there are no paddleshifts for the Fiesta, one of the problems according to VW staff I chatted with was the use of manual mode then shift to neutral to go from manual mode to go back to automatic mode, because when at neutral both clutches disengage and re-engage in a split second he says sometimes such re-engagement will cause damage to the transmission, because this is not the correct way to go from manual to auto 

2009 Hyundai Coupe FX - ever considered this car? Its an update version of the coupe. Its better looking and I think they updated the ECU or something because it feels abit more responsive than the pre-facelift models. I suppose they're pretty good either Hyundai didn't manage to sell many or many people enjoy it and don't want to sell it because there aren't much on the used car market.
2009 Toyota Altis 1.8G - it is only 4 years old but then its going for a very cheap price, people wonder why, actually it is a cruel joke from Toyota. This exact model outlook first have a VVTi & 4AT gearbox, later they updated this model with a dual-VVTi & CVT gearbox, that instantly killed this cars value. If you ask me having Dual-VVTi & CVT gearbox isn't that important (only for kiasu people) because normal 4AT gearbox are more reliable and the power difference from VVTi and Dual-VVTi in reality isn't that far, plus this is the top range 1800cc version its definitely got enough power 

2010 Nissan Sylphy 2.0 - don't misunderstand that Nissan cars depreciate alot, they actually hold their value quite well it is only because TCM always throw price and over-trade for customer trading in their cars, so bank evaluation after taking these into consideration put the loan-able amount lesser. Because of that you can purchase a top range model from this brand at such a huge discount only after 3 years of ownership. Its reliable and cheap to maintain (for its range).

I think its better you take a new Preve than a used Inspira, not worth it.