There are two differences between the 1.8L and 2.0L. The Ecu and the Crankshaft. Thats it... everything else is the same, well aside from some HP. As for the camshafts, motorsport has some optional stuff for the grand am cup. Check it out...

www.grand-am.com/grandamcup/rules_pdf/01_97-2000_Tiburon_nu.pdf

Headers, camshafts, valve springs etc.

-Steve

Here is some exhaust camshaft info

24200-23002 96-00 elantra
24200-23002 96-january 29 2001 tiburon
24200-23003 january 29 2001-end of 01 tib model

24200-23500 01-january 22 2001 elantra gls
24200-23501 01-02 elantra gls
24200-23501 01-02 elantra gt

The elantra gls 01 seams to have used both cams upto january 22 2001 based on the parts catalog. After january 22 2001 production, the elantra gls all used the gt cam

I don't know if this will help anyone or not.