Testing for leaks on your IC?

[New92]

Any suggestions? I was thinking of submerging in watter. I tried the starter fluid method but no luck. I start leaking when I am still in vacuum, roughly 10inhg. Currently I am running:
-Saab900 in top mount location
-1g DSM BOV
-MBC @ 11psi
-sti turbo back no muffler and the MUG

I noticed a very inconsistent performance in boost response as soon as I installed the tmic. If I hold steady at highway speeds I will hear a very loud whistle and the boost pressure will slowly drop with no change in the acceleration. I thought I had a bad bov and subsequently crushed and then replaced the original unit. I replaced any suspect clamps with t-clamps and torqued them to hellen back. What I noticed on the ic that has me wondering was a buildup of oil and gunk on the top left side at the intake side (not at the tb). Im missing the first inch or so of fins and there was a lot of crud sitting there. So I cleaned it off and went for another spin. Now the whistle is quite pronounced (it sounds like someone blowing on a flute or a bottle neck) so Im thinking that there may be a leak. Just want to be sure before I go and buy another one of these.

Any help is very much appreciated.
Ben