1. I recently switched my left suspension for a Gabriel Ultra because the stock suspension was leaking oil and making the car really unstable. Now that this is done, I feel that the car reacts differently and maybe a bit lopsided. Do I have to switch the right suspension as well? What do you guys recommend.

2. Second question, is anyone getting a really soft strange rattling noise when you are giving a bit of gas around the low revs of the car? If so what was the problem?

oh just for reference the car is a 2001 Honda Civic DX

Thanks

 

Shocks should be replaced in pairs for the reason you are experiencing.

second question is far too vague to answer without more information. Best guess is a loose heat shield somewhere.