Check out sentra.net and sr20forum.com - they have plenty of info on both the 2.0 liter (SR20 engine SE-R) and the 1.6 liter (SE, XE, E) cars.
The chassis code for the '91 - '94 Sentras is B13. The chassis is the same, with some minor suspension tweaks for the SE-R. Bigger sway bars, a touch stiffer shocks and springs, I believe.
I have a '92 XE that I started tracking this year. This winter I'm probably going to prep it for ITB. Next year the 1.6 liter Sentras are moving from ITA to ITB, so they might have a shot at being competetive.