Been to Wei Yip Cheras main branch, no problem with their workmanship, in fact I'm quite satisfied, just that the products there are all replica/cheapo items la...

I think only the parts that have been changed is voided of warrantee? Enlighten me. But then the radiator is caused by carelessness of the exhaust guys, just get over with this and get yourself a new replacement radiator. Try to ask the exhaust guys to pay half of it at least.