[Rails] Need advice: threads or Typhoeus?

Hi guys,

I need my app to make a few hundreds requests to external web services
as quickly as possible. The web services are fairly fast, but still:
if I do the requests one after the other, it is too slow.
My understanding is I have two options:
a- Threads.
b- Typhoeus

Typhoeus seems great. Yet, the web services are all quite different
(some are SOAP, some REST...) and therefore wrapped into interfaces. I
might be able to implement Typhoeus but it means a lot of changes.
I have read that threads in Rails can be challenging to implement
especially when dealing with the DB. Yet, this part of my code doesn't
do anything with ActiveRecord. Are threads generally "OK" if no
connection to the DB is involved?

Thanks a lot for your recommendations.

Pierre