I have a 2009 Giant Cypress DX. The first thing I did was put a Serfas RX seat on it, good move! I was getting flats almost once a week so I replaced the stock tires with Specialized Nimbus Armadillos which can take 100 psi, another good move! I got 700x38s but could have easily gone down to 32s (Infinity Armadillos), maybe 28s. I wanted a little lower gearing for hills so I replaced the crankset with a Shimano M191 (24/34/42), also a good move! On 60 and 50 mile rides earlier this year I was passing alot of road bikes, this thing is definitely faster than stock now. Consider carefully if such modifications are what you want, they were right for me, but might not be for you.