IMO, chassis realigning is a difficult task, BMW has the equipment to do it. But most of the Panel workshop in malaysia will have problem. Changing a steels profile will somehow reduce the durability. Process such as welding will also effect the quality of the frame since it changes the characteristic of the steel when heat is applied. "IF ANYONE HERE KNOWS WHERE TO ACTUALLY PERFORM A PROPER ONE PLEASE GIVE CONTACT!".
Try not to weld the chassis in the car is used for daily drive. I weld my wira 1.5 chassis and now it gives more load to my suspension and made my ride very harsh. But ultimately its up to you and of course the weld very much improve my steer response.
You can try using performance bars like the strut mount bar, fender bar & such to strengthen your chassis.
JUST SHARING