Hi Joabthebugman,
There are different versions of the 2007 motor depending on early or late editions.
The very early 2007 didn't have mushroom lifters or the aluminum intake spacer. Mushroom lifters are a MUST! not a speed item. All 2007 cylinders need to have the metal re-cured.
Mushroom lifters are now hard to locate and the price has increased to $95.00 for a set of modified lifters [stock mushroom lifters are way too heavy]. Factory mushroom lifters can be modified for approx. $25.00.
Modifying the cylinder is approx $100.00 [includes major port work, valve work, decking cylinder, etc].
Head used on all 2007 motors can be re-worked and modified for better flow [easier starting, higher MPG, more HP, idle smoother, run cooler, etc] for approx $45.00.
If you can buy for $400.00 and spend less than $400.00 to make it bullet proof & faster, it would be well worth the investment.
Have fun,