Current Projects chat and miscellany

My current setup is:

9 speed Tiagra STIs
Tiagra rear mech (not sure on the exact model, I don't think it's a long cage)
Tiagra front mech (double)
48t & 34t chainrings
12-27 cassette

I have the possibility of some riding with proper climbs in the not too distant future and after blowing out my knee last summer want to increase my range without fitting a triple and having to change my shifters. I figure a 34-32 ratio would make climbing a fair bit easier than 34-27.

What (apart from the cassette) would I need to change to fit an 11-32 or even 11-34 cassette? Thanks.

Fit any 9-speed Shimano MTB rear dérailleur; job done.

e.g. http://www.bike-discount.de/shop/a14755/deore-rear-derailleur-rd-m591-l-sgs.html?lg=en&cr=GBP

Ooooh this is interesting. I currently have a similar setup, old 105sc 8 speed STIs, with 38, 48 rings and 12-26 cassette. I'm wanting to go on a trip to the lake district, sort of light touring, including some giant monsters of hills (for my puny legs). Does the same answer apply to me, any new Shimano MTB 8 speed derailleur and cassette? Or would the cable pull ratio on the 18 year old STIs not match a new derailleur?