Here are some other parts you will need for SR20DE (140hp) or SR20DET (205hp):
Stock Mounts or place racing upgrades
SE-R/NX2000 Transmission
SE-R/NX2000 Flywheel
SE-R/NX2000 Clutch
SE-R/NX2000 Radiator
Rear SE-R/NX2000 Mount Bracket
SE-R/NX2000 Computer or if Doing DET swap, JWT programmed ECU or Almasi
Axle Carrier Bracket, needed when swapping from a 1.6 to a 2.0
SE-R/NX2000 complete Harness
SE-r/NX2000 Heater Hoses
Passenger Side Bracket for motor mount
just buy a NX2000 at a junkyard for pieces or if you dont have the cash or time to find these pieces just sell the Sentra and buy a NX2000 91-93 and the SR20DET is a bolt-in swap it will cost a LOT less of money and time