I took my SHO up for a canyon drive today and the summit was around 9,500ft. SLC valley where I live is around 4,200ft. Down there my car will ramp up to about 13.5psi of boost then start to fall to around 5500rpm down to 10.5ish psi. Up the road I took. WOW... It went from 13.5psi then at only 4200 It started falling fast down to basically stock 8.8psi. (reading my X4) Feels like it too. Extending 3rd gear out took FOREVER.
Ford put just enough turbo on these cars to maintain a stock boost level at high elevations. If I didn't plan on selling this car in 2 years I'd totally consider upgrading the turbo's.
