Good looking boat you have there. The 35 Sonic is a good size boat to run and handle the bay.
Most twin engine boats, the engine compartments are tight, with side by side installs, staggered setups= plenty of room.
One of the nice things about the 45 ( and a few 38 & 42's ), with the tripple engine setup, there is plenty of room around the engines. I have no problems at all. My previous 42 ( twin engines ) was tight, especially with the genny. My 45 has a genny with the tripples, and still plenty of room to work.
The $80k Sonic in Annapolis belongs to a friend of mine. Its actually a 94, all redone, looks like brand new, and its a 45 also. Tripple engine setups are standard in a 45, optional in a 38 and 42's. Very few 42 tripple setups were done. There were more 38 tripple setups produced than the 42 with tripps.
You will love your Sonic, not as fast as some in the same size range, but when it gets rough, most times they will be behind you, unless they like getting beat up pretty bad, but that also depends on what they are running in too, but for the most part they will be behind you. For size, ammenities, head room, strength and construction quality, they are hard to beat.
Good luck with the boat. You should have little to no issues with the Sonic, but that too depends on how she was taken care of. For the most part they are built like a tank. If you need anything, send me a PM. May be able to help you out if you need it or point you in the right direction.
Unfortunately with Sonic changing hands/ownership as they have over the last 10 years and also with the economy, not too may spare parts around, especially with the older hulls, and many of the OEM suppliers are no longer around.