I have a '99 RX 300. Have just over 200k on it now. Runs fine but lots of engine sludge. Was wanting to use some aftermarket engine flush but not sure of how to go on this or if they even work. Doubt there is any warranty available at this time but want to keep the car running well. Any suggestions? Also recently my flex pipe on the exhaust has started leaking and it sounds like a motorboat. Is this something that is replaceable by itself or do I need an entirely new exhaust system? Great forum here and very helpful