Thomson Elite X2 has the clamp size of 31.8, you will need to shim it again.
http://www.jensonusa.com/store/produ...+Mtb+Stem.aspx
Length and rise depend on you...what rise and length have you been using?

Cane Creek headset is good enough IMO.
http://www.universalcycles.com/shopp...9&category=104