Here's my guesses on what stuff should cost - others will have a better idea tho
Organic Clutch - $600 + $500 to fit
100K service (so timing belt, water pump, idler/tensioner bearings i guess) - maybe $1K all up
Alternator reco - $400
Radiator hoses (SFA unless they did all the coolant hoses, ie plenum off etc, which would be at least $500)
Splitfires $600
Compression check (this is very useful to know - your motor is in excellent condition) $??
So thats about: $3100 already, + comp test + some labour for the fitting of alternator/splitfires, so its seems in the right ballpark to me.
Re: AFMs , they wont both go at once, so just replace the stuffed one. No point it bitching to a workshop about your AFMs dying - stuff breaking is what happens on older cars. I probably spend around $8K all up a year on keeping my car running and adding improvements. I think of it as an investment to keep the car running sweetly and making it go faster...