Have a 2018 370 Sport with 21k...thinking of putting on a Stillen SC...bumping up to 400 hp...any tranny concerns or thoughts on other components...i.e.brakes...shocks?

 

Putting $3K into your car to go from 270hp to 400hp sounds like a win to me, it will be a completely different car. I'm finishing a Vortech V3 build and expect about 485. I'm adding Z1 test pipes, Fast Intentions stainless true dual 3", 24 row oil cooler, fluid damper crank pulley and an AEM wideband failsafe boost guage to guard the motor. Obviously a tune with UpRev to manage it all.
Before you jump in, read up in the Forced Induction sub-forum to educate yourself. Your time and $$$$ will thank me. Gl!

 

You will be just fine going Stillen SC kit; especially if it is the sci trim that comes with their kit; won't see 400 whp, but you will notice a major difference in power/performance that is great for DD and street and something that the stock block can handle. * I'd check if they can give you the Vortech Si trim if possible; that's what I've got.

 

$3k???

Last time I checked (just a few weeks ago while yet again entertaining the thought with a CA legal blower kit, of which there are none)... Vortech and Stillen S/C kits STARTED at North of $6k.

Be that as it may, going to 400bhp isn't too far of a stretch on the VHR. Starting at 332bhp means adding "only" 68 ponies. That's $96/added pony (for a stock block application), Not bad, not bad at all.

Unless OP is talking wheel. Woof woof, then it becomes a little more of a stretch and may require the second scroll of a TT.

On the overall, I'd say that the OE brakes on a Sport 34 are up to the task unless you're running WOT for extended durations. 4-pot/14" Akebonos with some good pads, all good. The other supporting mods like suspension and tires is a given. The biggest supporting mod will cost about half the cost of the kit too.... driving school. (And no, OP, not kidding nor dissing since I don't know you or your background but trust me when I say that the driver mod is MORE IMPORTANT than any hardware mods.

 

Sup Mic,
The $3K price tag is in fact true. I paid that for a used Vortech V3 blower, charge pipes, injectors, split-second box, 1 step colder plugs, small Mishi oil cooler, K&N air filter, , intercooler, a spare wiring harness and an extra pulley. I bought it off my350z.com Marketplace for $3K shipped. I had to contact Vortech for the mounting hardware as that was misplaced by the previous owner ($115). I went with a larger Treadstone TR12 intercooler for $225. I had all my charge pipes powder coated by a friend for about $100. I decided to go with ID 1050 injectors rather than the 400s the used kit came with but yeah, you can basically get a complete used kit for that money.

 

Ahh, pre-owned, gottit. I don't usually buy mechanical parts pre-owned other than wheels so never even considered that.

I don't know how the market is for pre-owned Z34 blower setups. Can't imagine it's as robust (relatively) as for Z33 but maybe OP will luck out.