I have gone the 'DIY' rebuild route a couple of times on the M100 Elan/Impulse RS and learnt that in the end its not worth it. Things change when you take them apart. The kit includes a new lock nut, which you should use. The problem is marking the orientation of the turbine and compressor wheels prior to disassembly is useless as the balancing is actually achieved by fine shaving metal from the nut, which you could also mark, but should be replacing (and if you try to refit the identical position it will not be tight enough). What happens if the seal lands on the shaft are worn? what happens if the bearing surface of the shaft are scored? or the cartridge is scored? Watch a couple of you tube videos on how they are balanced ( and you can see that its not just the compressor wheel and shaft that are needed to accurately balance a rebuilt turbo, you need to include the new thrust and the nut, which are now different from the one you removed) Turbo shops balance the shafts by grinding away a very small segment of the new lock nut (the actual turbine and compressor wheel are balanced individually, but then need to be fine tuned as a unit) At the very least if you are determined to do it yourself then just send the shaft, wheel, thrust and nut to the shop and ask them to dynamically balance it (Up here its $50) Keep in mind that these smaller turbos spin at around 200,000 rpm, the newer ones up to 250,000. On the small turbos they are prone to what's known as 'stackup unbalance' which comes from the new thrust and nut. I can change a tire on a rim, but I wouldn't leave the original balance weights on there. The web is full of guys who say they rebuilt their turbo no problem, but they seem to disappear when it comes to the 'how long did it last' question. I Just paid $200 to have an IHI rebuilt for my Impulse as I purchased the
correct kit and had them install it (stay away from these:
BEWARE of the DIY Turbo Rebuild Kit myth ! | eBay ) I get a full warranty and peace of mind.