1341 & BV Head with a K03 at ~21psi will make 200-210bhp dependant on rolling road. Probably the most drivable setup for the road and track, and has the advantage of cheap(er) parts such as turbos, cast manifolds, and off the shelf maps.
For 210bhp+ you could look into a K04-15 (K03 housings machined to fit K04 wheels) but these are expensive and usually custom built- similar price to roller bearing Garrett units. Advantage of being able to use off the shelf actuators, manifolds etc, should be able to hit 220bhp with this setup.
220bhp+ Into the larger Garrett units, GT22<GT25 requires more expensive manifolds/downpipes, most of the parts will be custom- unless you can TIG yourself a decent manifold/downpipe will set you back several hundred pounds. Custom map is required.
Extra to your spec worth considering is:
Water cooling for turbo
Extra provision for oil cooling
315cc/min Injectors (required for 200bhp+)
Uprated fuel pump
The reason for your peak power target is to keep up with your mates 220bhp RS Turbo, I'd be tempted not to try and match their power figure, but go for something which is tractable and drivable on the road, granted on the motorway it's literally down to power, but in 85% of driving it's all about transient response- which a K03 does much better than a larger Garrett unit.
You can always add a little giggle gas for when you really need it, I used a 25bhp shot on my K03 to go from 203bhp to 223bhp and it worked really well.
Hope this helps,
Pete