SilentKnight - YES you should - Little known fact about the S197 mustangs ..first the 2005 - 2009's have some of the highest production numbers EVER even in the face of the economic crash. The S197 had the MOST models of any Mustang era (I believe it was 87 unique models). Also in terms of customization, aftermarket parts, etc. ...AGAIN , highest of all.
So here is my advance from a guy that owns a 2008 Mustang GT California Special Convertible (check out some of my posts)
97K
1) Change the oil, tranny fluid and rear diff fluid - do it at jiffy lube and you can be done in an hour...or do it yourself - just do it
2) Change the Spark plugs - but here is the bad news - your 2007 has the dreaded 2 piece sparkplugs which if not removed carefully will break off in the head...NOT COOL. There are TONS of youtube videos on how to do it without issue but be patient and pay attention
3) Change the VCT solenoids (they stick up out of the valve covers) They are not expensive and again - YOUTUBE on the easy how-to
4) Change the coilpacks - stick with the original equipment ford ones because 1) Price 2) Quality 3) durability
5) Major but well worth it upgrades - If you never get past these two you will still be doing awesome
Cold Air breather and race tune - Going to cost you about $700 bucks for a JLT cold air breather and the tuner from Bama (kit) with tunes for life, but it unleashes the power of you Mustang - but you are then committed to 91 octane or better
Exhaust - AT LEAST just change the mufflers (I went with the Roush Extreme ) and get rid of the wimpy restrictive stock mufflers. EASY change do it yourself
Feel free to ping me for more info - and here are some pics to make you go hmmmmm