Engine Build List / Recommendations

[cmiguel32]

I've been a long time lurker on here and I've had my b6 a4 for close to a decade now. I caught the mod bug after going with a F21 Frankenturbo to replace my aging k03.
Now i'm finding myself in the process of acquiring parts for an engine build. My power goal is around 400awhp.

So far I have a spare 06A short block and I've purchased a fully built AMB head.

The head has:

Integrated Engineering Street/Strip Camshafts
IE Titanium Valve Spring/Retaining Kit
IE Valve Stem Seals
IE Valve Guides
Ferrea Intake and Exhaust Valves

As far as building my block goes, this is what I currently have as a parts list:

AEB pistons
OEM piston Rings
IE rods w/ rifle drilling option
IE Rod install kit (head gasket, etc)
Mahle rod/main bearings
ARP studs/bolts
New oil pump/chain/pickup tube
having the rotating assembly balanced and the block honed/decked and the head leveled

For my power goals, do you think the IE engine girdle is overkill?
Should I get billet main caps?
Is there a benefit to going with coated bearings as opposed to non?
Would there be any substantial benefit (considering my power goal) in going over-sized aftermarket pistons instead of B5 AEB ones?
Is there anything I'm missing as far as parts that I should be thinking about for the engine build?

I haven't even begun to do in-depth research about the turbo that I will eventually pair with this set up, but i'm thinking an EFR variant of some kind with an RAI manifold.
A stronger clutch is a given.

[fyremanpat]

for 400whp all you'll need is rods and HD springs. replace gaskets, guides, rings and bearings of course while youre in there.

[Furly]

You don't need oversized anything for 400wheel.
Your AEB pistons are more than enough.you'll actually be over built for that. But if done right it should handle it reliably.

Once you dig in, you'll find yourself replacing a lot more shit.
I ended up replacing everything because OCD.

[diagnosticator]

Realty check: With the HP goal you intend, remember the negative consequences. The drive-ability of the engine will be reduced on the street. Maintenance requirements will increase a lot, you will need to recognize when detailed maintenance is needed to avoid trouble and there is no general case guide for this. Break downs will be much more likely. The transmission,clutch, driveline, axles, and brakes are all under a lot more stress and strain.

[cmiguel32]

Realty check: With the HP goal you intend, remember the negative consequences. The drive-ability of the engine will be reduced on the street. Maintenance requirements will increase a lot, you will need to recognize when detailed maintenance is needed to avoid trouble and there is no general case guide for this. Break downs will be much more likely. The transmission,clutch, driveline, axles, and brakes are all under a lot more stress and strain.

I'm definitely aware of the perils of engine builds. This isn't my first rodeo. I built up a 1zzfe motor (forged internals) with a custom turbo and stand alone engine management back in 2003. It was nothing but trouble/constant wrenching. Then again, at the time, that motor wasn't as common to build nor supported by any kind of community of enthusiasts to the degree that the 1.8t is.

To be honest, i'm trying to overbuild this engine for the sake of reliability, with the understanding that issues pop up. I like the idea of a high reving 1.8t to compensate for some of the lag of a larger turbo. I'm looking at twin scroll variants to try to minimize lag even it if means getting a custom manifold fabbed.

My questions are more for folks who have built up their motors and gone BAT. I'm trying to find a compromise when building the engine so that i'm not going overboard, but that the build is more reliable than if I were to just swap rods.