Firearms are illegal in SG .. :bsmilie: SCNR .. but for your 40D there are many reputable shops listed. But, to make that point very clear and straight:
These are shops, their purpose is to sell things at "cost plus" where the 'plus' is aimed to fill rice bowls and bank accounts. None of these shops is your free adviser, product explainer, showroom guide... Which means: do your homework before you enter the shops. Read about what you want to buy, know the street prices, know possible alternative products and their prices, know the specs and features etc. If you don't know what to buy better stay away.
The weekly threads about shop uncles cheating unknowing buyers with cheap crap for ridiculously marked up prices should serve as warning.