I think with cores that size, the front bumper/reinforcement bar is not needed for crash protection. The huge size of the core is an excellent impact absorber, and will crush and slow the car down pretty good I'd think. (Especially if you use the stock frame horn mounting points like the old impact bar did, tying the front frame rails together.)
I'm using a smaller FMIC, but have the oil cooler welded up to the end tanks. (About 1/2 inch of attached metal on each tank, otherwise the oil cooler is 1/2 inch away from the intercooler so there should be minimal heat transfer. Also the cooler is on top, and behind of the FMIC, so heat rises, and airflow should be taking any heat away from the FMIC v/s heat soaking it from the hot oil cooler.
If I had just cut the bumper out of the way, it all would have fit in there no problem, but I wanted to maintain what I could of the bumper. I've since realized that to get more airflow over this, the bumper is going to have to be modified, but I want to try and keep the external "look" stock, and undercut the cover/impact bar to make it a bottem breather. It should draw more air up and over the core/cooler yet not look like it has some huge FMIC on there. (Sleeper aspect of my car is somewhat important to me.)
It is tempting to just ditch the setup I have, and go with a huge 4" thick core. (6 inches is even better, and provide better ground clearance due to a lower overall height needed to flow the same amount of air.) That being said, I'm nowhere near exceeding the 750cfm rating of the core I have now. (1350 is awesome.)
One thing to keep in mind. You do need some air for the radiator/condensor. I'm running my AC, and I have used a stock oil cooler for the PS system. I have a fluidyne radiator, and in traffic, with the AC on, the stock fan(s) are not getting the job done. (This is 103f temps.) I changed out the clutch on the fan, but I think the one I got is not much better than the one I had. (New they are too much
) The car does not overheat at any speed so far. (With the lower cover in place. W/O the cover, it did climb slightly at over 100mph, but I stopped since I really don't want to overheat the car.
Are any of you guys going to run a custom air dam or splitter/defuser type front undercover? I'm still kicking around the idea, and with the bottem breather mod to the front bumper, it would help to force more air through the radiators/coolers than without it. (And it should make the car more stable at higher speeds too.)