I have just purchased a 05 gx impreza it has new tyres but there is a shudder in the front end when you turn hard left or right is this cv jionts or just the new tyres no oil leakes

Depends on the noise and when it occurs. If it is a knocking noise it is probably suspension / bushes, if it clicks especially when turning it is CV joints, if it is under breaking and sounds like metal on metal it is brake pads. There are other issues like damaged rims, damaged tyre that can cause shudder / noise.

check and see if seal is damaged then try to push the axle back in you may have just popped out the axle from transmission if your lucky

You have one or more bad drive axles. If you turn the car to the right or left and the grinding or clacking gets worse you have one or more bad drive axles(cv joints). Your best option is to go to a Chrysler dealer and purchase factory rebuilt axles. After market rebuilds come with a lifetime warranty but will probably not hold up for more than a month or two. Any rebuilt can go bad (usually with in a month) but you will have better luck with Genuine Chrysler rebuilds, you will save time and money from not having to replace bad rebuilts. This is experience talking . If you have a shop do the job make sure the labor is included in the warranty. If you are driving or accelerating at low speed and experience a gentle shudder or shake. The low speed shudder can develop after hitting pot holes or speed bumps too hard. This is a sign that the inner joint of the axle is worn beyond service limits. Again , go to the dealer and buy factory rebuilt axles or purchase new axles.

Check for a damaged wheel rim- the wheel balancer should have detected this, but may have missed it.
Check for defective tyre- new tyres can have faults -rotate wheel while jacked off ground, look for bulges, lumps or tyre runout when rotated.
Check for looseness of tie rods and steering box etc.
Check wheel bearings are ok.

check the tracking....ensure tyres have not got any bad tread or wire showing

This sounds like there is something worn in the steering. If it is a rack & Pinion steering the rack could be worn out. It could also be the CV joints to the front hubs. Regardless it does not sound safe. Take it to an independent mechanic, NOT THE DEALER, and have it inspected. There typically is not charge to inspect/identify the problem.

is the steering over locking,and catching the track rod end
is it a wheel balancing wieght catching on the steering jiont
is it the hub bearing /flange worn or loose
is the brake caliper loose
are the brake pads low
is the back plate catching on the brake disc

Reserface rotors on car and spin balance tires and wheels.

sounds like a bad cv shaft. If there is clicking while making a turn, 90% of the time you will need a new cv shaft. The shudder also denotes a bad cv shaft (front axle) Most axle repairs cost up to $400. If you are charged more, find a new mechanic. if the car feels like it floats back and forth (side to side) Be sure to check the control arm bushings. If you are not sure how to inspect them, visit a service center. Any problem in the suspension should be addressed immediatley. Stay safe.

sounds like your cv shaft generally happens if the rubber boot on the shaft is split or broken