Replacing the throttle-body base gasket on 1991 Suzuki Swift

I'm having a little bit of trouble with my Swift/Firefly/Metro. It's the 1.6 5speed sedan, and I get a bit of rough idling, throttle stumble and when I downshift, I get the "BOM-bomomomommm" noise (I have a sports exhaust fitted) that you would usually expect from a rally car or something, but I don't mind that. What I mind is that under gentle or normal acceleration, I get a stumble, as if there's a miss. I Googled it up and found out it is probably a faulty throttle-body base gasket. Is it a simple on/off operation, or is it a bastard to do? PS Not from Massey, MD. In another country.

Asked by for the 1991 Suzuki Swift
sorry, all the info we have available is just for USA models which is a 1.3L engine. for that engine, it lists
1.1 hour for the TB gasket.
Thanks anyway, I should just bring it to my mechanic.