You can DIY in a day(assuming you have all the tools, and a mate or 2 to help lift the box in.
If DIY: a week before start using WD40 on every single bolt that will be undone to make the job easier, do it every day.
If a workshop i would imagine:
Remove Exhaust 30mins
remove box and diff 60 mins
remove, replace clutch and flywheel 20mins
Install box and diff 90mins
Add fluids 20 Mins
Test everything 60 Mins
This is for a shop that knows what they are doing, having a hoist and gearbox jack is bloody awesome, and you can always factor in no shop is going to get right to work and do the job as fast as possible to save you money.
I did a 6speed install into my mates 04GT gen4 last weekend, not the hardest job on earth, hardest thing is lifting the box from under the car, the bloody thing weighs more then i do.
If you need more info's PM me
