My turbo is sending oil through the exhaust and I have to replace it. I have removed all the bolts excepts the two nuts that that fasten the turbo to the exhaust. I have sprayed the nuts with penatrating oil and still cannot remove them. I believe I have not damaged the nuts. These nuts are really hard to get to and I have tried to use a 12mm open wrench on them. There is not enough room for a closed ring wrench. Are there any tips on how to remove these two nuts. My dealer in Colorado quoted me +$1800 for a replacement 4 hole turbo. Are there aftermarket turbo's worth looking at?