usually around $1600 in labor alone, parts depends largely on what you do with the turbos (rebuild, replace, or upgrade). If you're looking at new turbos, Sport 500's are generally more inexpensive than new stock turbos. I'm not sure what it'd cost to rebuild but if you rebuild you have the concern of how well it's done. So new turbos start at around $2000 (Sport 500's) and go up from there. So a minimum of about $3600 and that doesn't include new fluids and any other parts they replace while they're in there. $4000 wouldn't be an outrageous estimate.