Q: How do I redeem 'Mech Performance Steam Pack?
Once this has been completed, launch MWO through your Steam library and login to your MWO account as you usually do for your independent client. Upon this login, the Performance Pack(s) will be redeemed on your account.
Once these have been redeemed, you can uninstall the Steam client if you don't wish to have two separate MWO clients on your PC.