First off, yes you need an electronic flasher unit. It cost me like $12 from superbrightleds.com. It actually has room to slide in nice and snug next to the stock one, so all you need to do is unplug that one and move the plug over to the new one.
Do NOT cheap out on LED bulbs. You need to get SMD diodes if you want them to be around the same brightness as stock bulbs. This is mainly a result of our reflectors not really being the greatest for LED bulbs as they do not output light evenly in a full arc. Additionally, you want to ensure you get bulbs that match the color of the lenses or you will lose light output. For reference, I paid a lot for each one of my SMD bulbs ($24 each) and they are pretty much equivalent to stock bulb brightness... I think. Might even be a hair dimmer to be honest.