S15 to me is a nice and easy driving car. Handling wise, well, is depend on how you judge it good or no good, To me the handling is good , but i will partially agree that during the wet, things are a bit off-hands. For starter, you wouldn't want to go full throttle when overtake car in wet condition, that might make u end up in tiang, dinding, or lorry backside, You seriously don't want to do a big sudden turn on your steering unless, you try to do sideways. Then on normal brake system, you would just want to allow yourself a bigger gap between your car and the front car cause the braking power is a bit less in raining condition. Other than that, when is on dry surfaces road, it is just a superb car to play with...
Maintenance is slightly higher than a normal car, let's say a protong. First, the engine oil that you would use will need to be better, the cheapest but good engine oil will cost between Rm 230 to Rm 250. But if you use a fully synthetic oil on a proton it will also cost around RM 160 (I guess only) . Saying so, you would have to change the oil for a turbo car at the max of 7000km where else a protong can be done at 11000km . ( P/s One could also changes the oil for S15 at 10000km but is seriuosly not recommended)
Engine oil filter cost alsmost the same, gear oil around there , brake fluids, you can use normal brake fluids as use in protong (but again seriously not recommended) so is about the same. The only additional oil that one need to pay is the LSD oil that I don't think a Protong FF car got.. Spark plug, the stock standard are using No 6. plug and it can last the same as in protong car .What else......I think that's it. So the major price different to own a S15 and a Protong is (A) the engine oil (B) the LSD oil