I wouldn't let this deter you from getting a SHO. I would suggest you only looking at 2013 and newer, with under 50k miles and one owner AND definitely make sure you get a good extended warranty.
My problem was a horribly chaffing knock sensor wire. I changed out the entire harness and it's like night and day. I do need to replace my flex pipes, which I'm just going to get catted downpipes as soon as I get enough money. But honestly, the car runs amazing now. The vacuum leak I had was for my brake booster and it was a cheap replacement. I did have a leak from my PTU but I replaced the seal and I've had no smells, no leaks - zero issues with regards to that. I am pretty sure that the seal was compromised from the few times I had changed out the fluid since it probably never was before. But like I said, no issues there. I have zero transmission problems.
It was not the greatest to pay ( well I paid $1,400 for my main control because I found a coupon, but it was $1,700 ) and I honestly heard over the phone $700 and would not have said okay to do it had I known it was $1,700 because they couldn't gurantee the fix. I have a feeling that the reason it felt better after they did that, was because they probably touched the sensor wire that was sitting on a coolant pipe ( I think that is what it's called ). It sucks because the transmission expert should have been able to make a better assessment than to just say oh well it has a hard shift from 2nd to 3rd - well thats not super uncommon - especially just in normal drive mode and not sport mode.
Recently someone in the Milwaukee area with a SHO met up with me and took my car for a drive and his SHO is tuned and such and he said he isn't feeling any performance issues what so ever.
Bottom line, I definitely am going to be getting my car tuned (Gearhead) very soon because I've heard how much of a difference it can make and how I will be able to see how my car is operating better than just a regular scanning tool.
Don't let this get you down. I love my car. I will absolutely never take it to a dealership unless I specifically know the tech and specifically know he is familiar with the SHO. But besides my flex pipes needing replacement and some paint / rust issues on my trunk - I have no complaints.
It was a whole bunch of fuckery the past like 8 months prior before replacing my knock sensor harness and such but I am confident in saying that my boats in a good place and you should get a SHO.
