Reliability: Tuscan/Tuscan S Engine

[wantOneNow]

Gents,
I'm currently looking at swapping my boxster for a Tuscan. Could you kind chaps answer a few questions for me:

1) Regarding engine reliability - with the extra tuning of the S engine is it more likely to fail that the stock?
2) If I was unlucky enough to have a engine blow. What are the typical rebuilt costs (assuming out of warranty)?
3) Anyone got experience of dealers around Nottinghamshire?

[wantOneNow]

As I am most likley to purchase a used 2001 model, aren't the engines 4 litre in both the stock and S. Anyone now of what the main difference are that give the extra power and whether this tuning is more likly to cause problems.