Hey guys, I was just wondering why it makes this very loud noise, like the engine is hitting my firewall when i shift hard from 1-2 to second and so on. Could it be the motor mounts? How can I fix this?

 

Check all your mounts. Sounds like the rear mount is broke. It could also be the front lower mounts. I have a 99 Si as well and I added the Prothane Urethane Inserts to the pass, driver and rear mounts. Then I filled the front lowers with urethane window weld... The motor has never felt more solid in the car.. I highly reccomend this...