The flywheel was very noticeable. Revs a lot faster. Idles great 650-700 is smooth. With less rotating mass you will see the RPM's drop faster between shifts. I used a 16V fly wheel. If you use this, make sure the TDC mark is in the exact same place. I had to use a dial indicator through the #1 cyl to remark the TDC line. So, just remember to double-check everything.
-JB