i just want to no what would be better and faster

Depends on the intended use... Capacity and/or a turbo alone wont make one engine outright better than the other.
At the end of the day its comes down to the $$$ investment and selecting the right parts. Either option can be made to haul.

well iv got an a15 at the moment and mate is buliding an a14 with a turbo but as i am a p plater i cant turbo it and im wondering what i can do to make mine quicker that his its a standed a14 with a turbo

I think you will need to do quite a bit of work to a std A15 to match the A14T. 100CC isn't that much extra HP compared to what a turbo could add.

what could i do i have 5 grand sitting thier but im not sure what to do

Depends on what you have access to - I'm a fitter so just about anything is possible (well... how much time do I want to spend on it is the question here) but I'm not sure what you have access to.

This is what makes the cost vary heaps - how much work you want to do/can do your self.

Common NA mods involve...

Cams - more duration, lumpier profile.
Porting - clean up and open up bowl/guide area, port matching
Heads - find your self a A14/A15 oval port if you dont already have one
Exhaust - headers (or even stock manifold) with a 2" system
Intake - goes hand in hand with carbs
Carbs - Webbers, SU's or to be different; motor bike carbs (looks best!)
Pistons - Hi comp (forged if you have money to burn)
Crank - Polish and knife edge
Rods - Polish and lighten
Flywheel - Lighten plus drill
Springs - higher shut pressure on the valves
Retainers - Ali or titanium valve retainers
Push rods - lighter ones
Crank Pulley - lighten, smaller for less fan rpms
Rebuild - rings, seals, bearings, oil pump, water pump, ARP bolts
Roller rockers - only really good if you have cut valve guides or tons of money for bling and requires the mandatory perspex rocker cover!
Sump - baffles + larger
Balance Engine - blue print rods too
Bigger Radiator
Electric Dissy

Last but not least a TUNE! Get the carbs running smick and set your timing (to what fuel you want to use) or all that work is wasted.

I think Ive covered all the mods beside silly things like making custom cylinder heads or full race mods like larger valves, etc.

Talk to bige on the forum here, he seems to have a good reputation for making these A series hum.

im making a series turbo manifolds if your interested mate?
http://datsun1200.com/modules/newbb/v ... hp?topic_id=44398&forum=1
heres the link
cheers
Dan