[sdiy] transistor socket recommendations?

[cseldridge]

I'm looking for some transistor sockets to hold normal (sized) 
transistors for some circuit testing.
1. Anyone here have a good link to a US supplier?
2. Can transistor sockets negatively effect circuit performance in any 
significant way?

PS - anyone here dealt with www.cpcares.com?  I'd just like to know if 
they're OK to deal with.

Thanks in advance!

Chris