You want best flow or best power?
There are 3 LTH's. PPE, FI, and Motordyne. Motordyne are the new kids. From the little I have seen from them. They're not bad. I have the FI's.
The right side will take you less then 2 hrs. Depending on you skill level.
As said above. The left side is a PITA. The heat shield can be a PITA. Figure on about 6 hrs.