all tech details you can find on wiki, from the start to the present model of engine lineup, so u can get a gud knowledge about this.
i have a GT too... decent ride. parts are available with the agents m sure u can find from other shops as well... n i think any garage can handle the engine coz right now there are much more complicated engines available in the market.
but dont just give it to any bloke to fix it
if the engine is well cared for...it would be a decent buy. hv no issues with ma ride very pleased with it, no issues found so far