I'm in Adelaide and my 4spd box is well and truly at the end of its life @ only 100,000k's I got quoted $2800 to be rebuilt buy a specialist with turbo gears which they led me to believe are a lot stronger. They also told me that it's a very common problem with the N/A once you put a little extra power through them. This could be wrong but I was also told that the turbo gears run a little bit lower ratio which could help a little with take off. TIP - why not put a 3000rpm stall converter in while the box is out you have put in a trans cooler but the extra money you spend now will save you money in labour down the track if your chasing some performance. Everyone agrees the n/a's are way to slow in the bottom end. I suppose it depends on what application you want it for. If your only aim is to do it on the cheap then $900 for a second hand N/A gearbox From Blair Athol Ford Wreckers or $1500 for the turbo box uninstalled. In my opinion if you have the money rebuild yours as then you will know the history of the gear box. I know your probably not in Adelaide but I hope this helps. Cam.