I'm not going to chastise you for the stickers, or the "conversion" But I have been riding Fixed Gear here in Tokyo for about 4 years and have learnt a thing or two.
1. FG no brakes is ok. Most of my friends ride that way. I don't promote it, but I do condone it.
2. Get foot retention. Clipless or nice MKS Sylvian tack pedals with straps.
3. If you run a brake, put it on the front, it looks a lot cleaner not having the cable run all the way to the back.
4. Don't be a wuss, take off the freewheel and put a fixed track cog on it! and do some mad skidzzzzzzzzzzzzzzzz........... Seriously, it's really fun.
Here are photos of my FG bikes so far. No Keirin frames yet, but I have ridden a few.
Masi Speciale LTD with track converted Rev X wheels
Fuji Track Comp with Modelo brake hoods for hand position, (only the front is connected to a brake)