The power band on the 2.0 liter turbo starts falling off around 5700 RPM and redlines at 7K. Don't worry about higher engine RPMs and engine longetivity on these Subaru flat-fours. They are well-designed engines.
I had a 1990 Mitsu Eclipse GS Turbo for 13 years and put 274K miles on it. The car was in good shape when I sold it. That was another well-designed 200HP four-banger (the same Mitsu turbo is used on the WRX.) Change the oil and filter every 3-4K miles and they last a long time.