if its for a race engine 4 into 1 would be best normally and 4-2-1 better for street, but the JTS would have the reputation and i bet probably tuned length, if its for racing u want the best which would be tuned length for every last hp edge.

j-mac, 4 into 1 are most popular on 4 cyls now because most afre fwd and work out a lot neater fitting with the limited room between block and fans, they often do end up with massively long primaries snaking right under the engine and make peaky powercurves with gutless bottom end. I think u meant straight 6's about the tri-y's.