I don't have and haven't used a tremolo pedal (but they sound fun on YouTube!) but from a bit of digging around on TalkBass: lots of folks like source audio pedals - seem to be very versatile. (Too complicated and ugly for me though.) There is also a good deal of love for the solidgold FX Stutterbox (and they have a new Stutter-Lite) and for the EarthQuaker Devices Hummingbird. I have a couple of pedals from each of these companies, and like them very much. I think I would want tap tempo on a tremolo pedal. cheers
in my opinion link, you really wouldn't want a floyd rose on your bass. i don't think it's something you would need (unless you want a whammy bar?), and having it intstalled could cause a laundry list of problems. if you find soemone whos good at what they do and you get good parts you could try it. but if you're looking to get it done cheap i wouldn't even bother.
Learned about this one recently: Seymour Duncan Shape Shifter. There's a pedal addict I know of and this is The tremolo pedal for him. It has remained on his board while every other pedal has been bumped by something new. The video makes it look and sound quite versatile. I've been able to play with one and liked it very much (much more than the EBS, which was very noisy).
This is an old, now discontinued product. You can find them on ebay and Reverb for as little as $60 for a used one. There's an New Old Stock (means it's been sitting on the store shelf for a long time and is unused/new condition) Shape Shifter on Reverb for $150.