As I recall that X-member is shaped quite different from oem. I take it you've seen pics of the install not to automatically go with the shop's presumed orientation. If everything else is the same then the fix from your description would simply be drilling a center hole, not adding plates to do the same thing.
Now since I've been absolutely no help I have a question: Why do you need that on your FWD - especially if sticking with the automatic? I know you're doing headers, but I did Tri-2 on my SS without changing the X-member.
\'96SS SOB: SSRI, Herter Tune, Tri-Y II, , 3000 Edge, F/HO bars, METCO extendeds with CV MMC, Bilsteins, currently Vredestein Ultrac Sessanta (315/35 rear). Finally, wait for it... LT-4 knock module!
\'96FWB BUW-Butt Ugly White: PCMPerformance tune, HDFA w/ swissed filter, 1/2 SLP s.s. catback with H- and Flow Super 50s, oem opti rebuilt 3 times, SS Bars, METCO LCA, Airlift 1000, Monroe SS, PowerTrax No-Slip, CTS wheels with +1 rubber. Finally, yes again... LT-4 knock module!