I think you're going to get differing views on this one. I don't think any Peninsular Malaysian species are true highland species, most are prettymuch intermediates. You'll find that ramispina, macfarlanei and sanguinea all grow well in intermediate conditions, tolerating reasonably warm nights, although macfarlanei has a reputation of disliking low humidity.
Personally, I have found N. ramispina one of the easiest Nepenthes species to grow. I grow many of them (although some have now been identified as ramispina x sanguinea). They all continued to pitcher during summer in Sydney, where the nights get quite warm, and the days are fairly hot. Humidity averages at about 60%, but you get both lower and higher during the summer season. My ramispina continued to pitcher more readily than most ventricosa and sanguinea varieties which seem to stop for a couple of months during the hottest weather.
The only thing I can go by is my personal experience, which tells me ramispina will grow as an intermediate. However, I know people who've had endless problems with this species. Growing conditions vary so much, and I find some species easy that others find hard, and vice versa. A lot will depend on your particular conditions (temps, water, humidity, light etc), and you'll need to give it a go to find out.
Hamish