[Tishabet]

Indeed, I lived there in 2011 and 2012 prior to moving to the states, great city. I will PM you to get your email address as I literally have aword doc of coolstuff to do in KL thatmy wife wrote up for the many friends who visited us. I lived right across the street from the petronas towers, above KLCC station on Jalan Ampang so I know that area particularly well.

If you have two days, I would highlight the following:
Batu caves:take a taxi from klcc, insist that they run the meter
Petaling street: a tourist-heavy spot but good for getting some trinkets etc to take home, haggle like hell here.
KLCC park: a really nice place for a stroll, right in the downtown core. Stop to watch the fountains outside of the mall.
Kaya toast and teh tarik: there will be numerous places selling these breakfast items, kind of the national brrakfast. Kaya toast is buttered toast with kaya, a sort of jelly made with coconuts. Teh tarik is "pulled tea" meaning strong black tea with sugar and milk, poured at a height from cup to cup to put a good frothy head on it. Delicious.
Char kway teow: my favorite street food dish, this is a pan fried noodle with some duck egg, shrimp and cockles. I think the best one in the city is at a fantastic food court (food courts are a seriouscuisine way of life in KL and Singapore) in the basement of the mall called Lot 10. This food court is not to be missed. Finish off with an iced cendol to really go full KL.
Eat dinner one night at Hakka Restaurant for real Straits Chinese food, really excellent. Fair earning that this is an outdoors restaurant.
Visit a Chinese temple and a Hindu temple, I have a few to recommend
If you like electronics there is a mall called Low Yat which is intense, a full sized mall (5-6 floors) of nothing but electronics. Excellent reflexology foot massage place there too.

I will think of more but this should get you started. Are you flying in via Singapore or via Dubai?