Hi (Bien venue) and welcome to the Black Thunder family! As for Whipples, they do make a wonderful package giving all around balanced performance. However, you will tear up outdrives. the 500EFI with Whipples will develop about 700 HP at the crankshaft and over 740 lp of torque. All that torque happens in the mid 3000 RPM range.
I was willing to put up the with the drive issues because (well because I'm really stupid) and also because I really enjoyed the performance of the Whipples. (Mine was a 43 with triple 500 EFI's originally) We would cruise at 3200 RPM and 63 MPH all day long. Several trips to the Bahamas and Key West getting about 1 MPG. We ran in the upper 90's at WOT with P-5 Hydromotives, 29 pitch and 1.36 drive ratios. With 34" labbed Bravo 4 blades at 5450 RPM we ran 97MPH. I found a better mid range and better overall ride with the P-5 hydromotives. Got on plane real easy, stayed on plane at 25 MPH.
So, if you go with Whipples,(Dustin Whipple and his Dad are good people, straight forward, helpful and a pleasure to do business with) plan on spending about $9,000 per engine for the Whipples and install cost. Then plan on upgrading to XR drives, and new props, there goes another $7,000 +/- per engine. Those 500 EFI's are looking pretty nice right about now, aren't they

But I'll bet you'll do it, because like the rest of us, you're nuts and want to go faster.
When you do, call or e-mail me and I'll be happy to walk you thru the install, best props, gear ratios, mounting for fuel pumps, plumbing etc. The fellow that now owns my boat is in Southern Pennsylavnia. Maybe you can make arrangements to visit him and take lots of installation photos to give you some ideas? He's a really pleasant fellow.
Congratulations again on your new boat. You're going to love it. The Black Thunder is a rock solid boat, great people build them, and the follow up service is second to none.
See you on the water,
Steve David