for shirts - you need to visit Great Stitch in co-operative market, their cuts and tailoring is really good for shirts. They also started to make mens jacket suits but I cannot comment because I never used their service for suits
there was a tailor on Abdullah Haroon Rd (Victoria Rd) that holds a real old shop, The shop claims that it made suits for MA Jinnah himself. I have used their services a few times and they make really good stuff if you can afford the time they take.
Moosajee fabrics are good too but their tailors had lost their edge when I visited them.
btw - reason to have shirts tailored for me was that apparently being 6'5" and a bit heavyset is considered abnormal in Karachi and hence no stuff exists for purchase. - Same with shoes - size 14W (US) or 13(UK) is abnormal - young's footwear had my size though but in one or two designs and shades only.
