Go the deeper keel
Standing rigging about $7k including turnbuckles
New diesel about $12k plus fitting

Ilenart said..
lydia is spot on with costs. A shallow keel will not perform as well as the deep keel upwind. By how much is hard to estimate.

+1

Rebuilt Kubota's are about $2400 on eBay. Full rebuild kits are surprisingly cheap.

Ilenart said..
A shallow keel will not perform as well as the deep keel upwind. By how much is hard to estimate.

Madmouse - hope this helps.
Azure is 30' and a shoal draft version at 1.4m compared to the std version at 1.7m. There is a std F305 not far from me and we often sail in the same area. Comparing the two, the boat speeds are pretty much the same, pointing is also roughly the same when we both have the same headsail up, but where I really lose out is the leeway. If we were racing id be at quite a disadvantage, losing perhaps 30-50m or more(depending on the tide) to leeward on a average 1nm tack. For cruising of course that doesn't matter to me*.
Also, Azure is a bit more tender in gusty conditions.
(*i get my racing fix on a mates 9.5m lightweight flyer)

Edit: I'd also add that in perfect light conditions with no tide, I reckon there'd be really not much between them.