turbo internal upgrade?

I have a big 16g turbo and the blades are all messed up on it..guess it sucked somethin in, well anyways i heard that you can upgrade the internals for it and make it a 'sleeper' 20g turbo? i've never heard or seen it before..but then again im a newb but around how much would it cost to do that? thanks

you're effectively looking at doing what FP has already done:
http://store.forcedperformance.net/merchant2/merchant.mvc?Screen=PROD&Store_Code=FP&Product_Code=NTDSMFPSleeper16G&Category_Code=Turbo-FP

They won't disclose their parts, but IIRC, I was told it's a 20G slapped in a 16G housing.

Now, I'm not sure if you would have to machine the compressor housing but the 20G wheel might fit into the housing.
Here's the specs on the compressor wheels:
Turbo ................Ind.......Exd....Comp housing
"Large" 16G...16G 1.892...2.680...16G
20G ............20G 2.070...2.680...17C

The turbines are the same
TD05H 1.9302.200070 - 7cm

or sbr, with the bastered 20g...

The comp cover will certainly need to be cut for the larger wheel. You can stay with the 5H turbine side, but I prefer my 20Gs with the 6H wheel.