First thing you NEED to do is a compression check. Dropping $2k-$3k on a turbo setup and then dropping a rod and/or piston would suck. Seek ye a Helms manual for guidance.

Some things you may consider replacing before you boost (depending on mileage and up-keep):

1. Water pump and timing belt (possibly oil-pump)
2. Complete tune-up
3. Clutch

That's all I can think of right now.