[brucepick]

Good to see you're working towards improved mpg in this car. We drove only RWD Volvos for about 10 years and I did much of the maintenance. They were great cars!

You mentioned an undertray. Don't underestimate it or let it drop off the radar. I found a lot of benefit from the one I built for my Civic.

Grill block is some of the best low hanging fruit. I strongly recommend a digital temp readout though, if using a grill block. Especially in your case with a turbo. You don't want the rad fan coming on; the power to spin it will cost you in mpg. ScanGage will show engine temp; I imagine UltraGauge would also.

Remember - 2 mpg sounds like "only" 2 mpg. But in your case it's about 10% of your total yearly fuel bill so =$$$$. 4 mpg improvement is even more savings for you.

Good luck with it!