Brake upgrade\wheel related question

[Bizzeh]

I've just been pointed over here from the '68 and up forum so sorry for the thread repost but...

... I'll start off by apologizing for starting yet another of these threads about brake upgrades, but a lot of the old threads I find link to stuff that doesn't exist on the web anymore.

I've recently acquired a set of 17" Porsche Twists (staggered 7 & 9", ET55 offset) off of a Boxster. As you can probably guess, the front's are VERY cosy and the rears are currently a complete no go.

Before I go down the spacers route, I want to take the time to upgrade the brakes on the car to something a little more current with the thinking it'll increase my track a whole chunk, hopefully by enough (unlikely though I know) to negate the use of spacers on the rear. Front's literally need 15mm extra to clear to tops of the suspension turrets (ball joint bug) and as i'm going to be getting a new beam on the car at some stage, I could get a bit shaved of the top of the beam turret too.

My current plans consist of going out and buying a new set of front VW discs and rear drums, get them drilled to a 5x130 offset and machined down into hubs and my local shop and mounting a more current Porsche disc/rotor on them.

What i'm in that dark about is the measurements for the brackets to mount calipers on and the right choice of disc\rotor and calipers for what i'm doing. My current line of thought is telling me to use the setup of off a commonly made model that would provide plenty of parts availability. I've been looking online and it would cost me less to buy new 2.7 Boxster discs and pads from a trade supplier than to buy 30 year old 944 stuff from eBay. Calipers also don't seem prohibitively expensive 2nd hand.

Is anyone running a Boxster (or such) setup on their car and gone down this route? What are my choices for a wider brake setup on the rear that won't compromise my breaking bias? What have I missed as I have no doubt that I've failed to consider something!

As always, any and all advice more than welcome!