Yes it is definitely more work than I realized from reading Dan Chadwick's thread. I suspect I would have been finished months ago if I had decided to stick with the stock fuel system and plug the holes in the XS LIM. He mentioned that he needed to add about 20% fuel to a previously tuned map after installing the XS LIM and performing some minor port work on his most recent engine build... I'd be pretty happy if I picked up an additional 5-10% power compared to the stock LIM... that would be 10-20whp which isn't too bad.
Good point regarding thermal expansion... I'll have to ask some Mechanical Engineer friends of mine to give a ball-park estimate of how much the turbos and manifold might grow when they get hot. I suspect the answer will be less than 2mm. I had some aluminum injector spacers fabricated and the outer diameter was about 0.001" larger than the hole that they needed to slide into, and someone suggested that I freeze the spacers and heat the manifold because that might make the cold parts shrink and the warm parts expand enough for everything to fit. I was skeptical so I borrowed a set of calipers to see the results of thermal expansion. After putting the spacers in the freezer they shrinking by almost 0.001," using a heat gun to heat the manifold so hot you couldn't touch it resulted in the injector holes expanding less than 0.001" (maybe 0.0005" larger). The result still didn't fit. When I purchased my XS fuel rail I asked them what they recommended for installing top-feed injectors in their LIM. They sent four rubber spacers which are apparently OEM parts used for the injectors in the FC3S. They actually said that the injector holes in the XS LIM are slightly smaller than the OEM FD3S LIM because they wanted a tighter fit with these rubber FC3S injector spacers. The fit is great, they are the thick black spacers in the photo below, I will use them instead of the green lower o-rings that were supplied with the Yawpower injectors.
I also decided I'd like to re-clock the vacuum port on the AEM FPR so it points toward one of the vacuum ports on the rear of the stock UIM. The top half of the assembly can be removed and rotated, as explained in their instructions:
