I don't think their design is "the problem" its just done that way to utilize space. I can see where you'd like to run it to the drivers side, haven't seen it dome, don't know if it will work or not? But really anything under an xj Hood is going to heat soak short of running a tube directly forward and down to fresh air... I was just hitting on the facts of its not a cai, at all. Its done to have a little extra protection when water becomes an issue, about 4" or so difference. And ABS or PVC will get brittle from heat cycles in the engine bay, ABS can even melt.
I did plumbing for new buildings in Las Vegas for about a year and any time we dropped off ABS on a job site we had to.cover it from.the sun if it sat longer than a week.
Experiment with it, or buy the kit.... its funny how threads like this start asking if people have done it and when people point out negatives the op fights to say they are right to save $20... go build it and report back in a year