I pulled my 280 out of the box and checked it (waiting on exhaust manifold, due today). The entire trailing edge of the turbine wheel is visible. Do you see any indications of DOD - Domestic Object Damage - dings, missing chunks, etc.? If not, most likely your blades have not been compromised. You could get a cheap borescope with a small radius snake and check the entire turbine wheel. If there aren't any significant dings on the leading edges, or any missing pieces on any of the blades, you're good. If you find damage that would lead to an imbalance, you'd need to address. If nothing is missing, but you see indications, depending on extent, it may affect turbine performance. You can also check the scroll, but if the blades are good, your scroll will be fine. You shouldn't have and FOD on the compressor side (Foreign Object Damage), and if the turbine wheel looks good with your eyes, you are likely ok. Just for reference, I'm at 35 years and counting in Gas Turbine / Jet Engine business. Borescoping compressors and turbines is routine to assess FOD or DOD - we don't take apart a jet engine to check it's too expensive, and in the power industry, it can cost millions to take an outage to take apart a gas turbine to inspect it. If it was me and the turbine wheel checks good, I'd pump a bunch of low viscosity oil through it just to be safe, and be and at least feel good about the turbo.