I'm going to be buying a 2006 XC90 next week, but can't decide between the 2.5 or the V8. I have had great success in the past increasing and chipping other turbo cars for great performance, but not familiar with Volvo's. Fuel economy is an issue, but that Yamaha V8 is a sweet motor. How much HP can I get out of the 2.5 with good reliability?
Any advice would be great...

 

Can't say I have experience with them having never seen one before but I am guessing it may be fairly simple.

It looks like there aresports betting two tubes missing from your photos, that link the two intercoolers to the carburettors.

There is a bit of history about the Janspeed setup on this page.

http://www.roversd1.nl/sd1web/jspeed.html

It looks like Janspeed attached the SU carb to the end of the turbo, where as your one seems to have the carbs in the standard place on top of the engine. I didn't think you custom pool builderscould use the SU carbs under pressure as they rely on vacuum to lift the dampers in the dashpots. Maybe these carbs are modified to cope with forced induction.
Looks good, although it May need a bit of a clean

Any idea what size the engine is?

 

The v8 is a very powerful engine for its small displacement. To be honest the 5cyl turbo in the XC90 is sluggish ( to me). Both are reliable. Personal choice would be the V8. Volvos arent that good on gas to begin with