It'll definitely be a change in regards to power. The IS 300 (217hp) has ample and more responsive power whereas the CT (134hp) is a bit slower but makes up in mpg's (43 city/ 40 hwy). Your IS 300 might have more space than the CT. You can fit five people in the CT but more comfortably in the IS 300.
I love my CT and purchased it back on March 2011 and have over 70,000 miles. It's a great daily driver and commuter car. Not only will you save on gas but also maintenance. The CT does have a nice sporty look to it.
If you can, keep the IS 300 and get the CT 200h.
2014 Starfire Pearl GX 460
2011 Smokey Granite Mica CT 200h
1998 Red SC 400 - Gone but definitely not forgotten
1996 Star Sapphire Pearl GS 300 - Gone but not forgotten
1996 Classic Green Pearl ES 300 - 400,697 miles R.I.P.
Last edited by Trexus; 05-23-14 at 12:51 PM..