depends how u and u're fren spend during the trip. for example stay at hotel or hostel things like that. whether u all shop a lot of always go restaurant.
let's say u all stay at backpackers hostel and take public transport eat cheap street food Rm1000 is sufficient for 1 week excluding the air ticket. If not, U gonna spend till at least Rm2000.

there u can get bus like rapid KL but far more efficient than that. If not mistaken can get daily unlimited pass so it's not that expensive.
Let's say all of you in the group are the type that can limit down the budget then I guess it would be sufficient though if u wanna eat like hell it wont be so possible too. Cosidering food in Taiwan is like higher a bit than KL price. Depends on how many place you go too.
can check out this website which i think is useful for you. www.wikitravel.org

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Added on December 13, 2010, 1:37 ambetter to prepare extra in case run out of money then i guess u gotta work illegally there to fill your stomach. haha. =)

This post has been edited by beederbest: Dec 13 2010, 01:37 AM

should really fins some time go taiwan.