Actually I would not specialize the chain for Rap. A good chain belongs much more to the individual voice and how it should sound in the context of the track than to the style of music.
You may get good results with McDSP, UAudio, URS, Metric Halo, Sony Oxford, Waves SSL or Rennaissance (List of my priority. Actually I do not have much experience with the Sonys!).
My chains for most rappers and singers in the last months was like this: Recorded the voice through the BAE Pre with the Peluso 2247 or sometimes the CAD E350. Mixed with URS Nevestyle EQ and 1970 Compressor (alternatively I found my hardware compressor often much better The Ted Fletcher or sometimes the Alan Smart). For reverb I used the internal Plate Reverb from DP5 or the Waves Rennaissance Verb/Waves IR1L.
I often switched betwenn EQ Pre or Post Compressor. Depended a lot on the signal I had!
Good luck and remember: The best unit in your studio should be your ear!
P.S.: I fear the same as SubaroOo does. Please use the plate as a send effect! Inserting is possible, but you should know a lot about mixing before you do that!
Mics: Charter Oak SA538, Peluso 22-47, CAD Equitek E-350
Outboard: Brent Averill 1272, Ted Fletcher TfPro P10, Alan Smart C2M, ELI Fatso
Computerstuff: Old MacPro with Logic
New Stellar Audio Windows workstation with Cubase
I have more, but my old list was deleted!