Pipework is pipework, silicone joiners should be decent with high boost cheaper ones have less ply in them (even with the same number of layers they are always noticably thinner). They come with 6 weaves for example IIRC but the amount of silicone between the layers is minimal. At high boost cheaper ones can fail, but pipework just get the cheapest you can as your never going to pop alloy tube however poor quality it is.
Make sure you get decent clamps as well. Mikalor clamps are the business, they are seriously wide and really meaty. I'd keep the piping the same diameter as he turbo outlet as a minimum mate, that way its performing its best but Im still not sure if you'd see a difference. Maybe some guys on here with some spare clamps as they aren't cheap. JamieP has a wall full of them once!
My mate at Boostjunkies.co.uk sells silicone joiners from a new company, and the quality is amazing, they are alway alot thicker and stronger than any samco hoses. And samco hoses aren't as good in my opinion. After seeing his range of hoses I was seriously shocked how thin samco hosing is!
I'll get a comparison of his hoses if you want just to proove what cheap vs named brand vs new products looks like if you like? Being a small company they are trying to produce the best products possible for the best price so they can grow and contend with the typical brands. Samco are a good product don't get me wrong, but I've definitely seen better, thicker and more durable material used with smaller companies.