I've had luck rebuilding turbo's myself. I usually go the extra steps and have the parts acid washed and/or media blasted so their immaculate. Balancing is usually okay as long as your compressor wheel isn't all chewed up. Make sure you get the torque specs on the compressor nut! That's really the only critical part during assembly.

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Current Stable:
01 ML55 AMG
92 500E (a few mods)
87 300E (lots of mods)
00 Chevy 3500HD Diesel Box Truck
68 18' Donzi Marine
06 GT i-Drive7 1.0 Mountain Bike (with GPS!)

PREVIOUSLY OWNED:83 300SD, 87 420SEL, 88 420SEL, 90 420SEL, 86 560SEL, 86 190E 2.3-16V AMG, 94 E320