hi just had a call from local garage - i took it in with the car in limp mode its a Range Rover Sport 2012 and also weeping a bit of oil from the rear - this has been diagnosed as a split left hand intake manifold causing the limp mode and leaking rear ARC bar - what would be the average cost for these works? been advised they might as well replace the pipes due to corrosion with the body off - the quote for the works seems to make it not worth repairing -I spent just over 3k on it in march to have all the suspension arms replaced then 600 to have disks and pads all around in June, the belts and pumps were done last year but this could be the end of the road for it

Might be worth a second opinion and quote.
Use JAS nr York Visitor from fullfatrr.com
* GONE. 2012 RR Sport HSE SDV6 Orkney Grey. Now being piloted by RRSTDV8
* GONE: 2011 4.4 TDV8 Full Fat. Amazing piece of kit.
* Current. 1974 Lightweight 2.25L petrol. Old skool
* GONE. Freelander GS TD4 Manual MY2013. Orkney Grey with privacy, cold and clearview packs, armrests (a must!) and a spoiler.
* GONE. Range Rover Classic '93 200Tdi Factory fit
* 1949 80" in family since 1975

Split inlet manifolds are a known issue. If you're going to do one, get the other done at the same time - the cost is in the labour of stripping the gubbins off the top of the engine. Doing both at the same time doesn't add much labour time. The manifolds are less than a couple of hundred quid each (https://www.advancedfactors.co.uk/inlet-manifolds--engine-cover-11658-c.asp).

The rear ARB can be replaced without lifting the body fully off. But if you're going to lift the body, replacing the fixed brake lines is a no-brainer. Dead easy to do then and cost very little in labour or parts. I had mine done when the body was lifted to do the cross over pipe. To be honest, if I was having the body lifted to do the ARB, I'd have them do the crossover pipe at the same time. It will be corroded and will need doing at some point and it's a body-off job to replace it.

Pay to have the body lifted - a couple of hours labour - and then other jobs can be done quickly and easily because everything is accessible.

Definitely worth taking it to a decent LR indie, not just a general garage.

If you have the suspension done and the brakes done, getting the rest done means a well sorted RRS which should give miles and miles and enjoyable motoring for ages to come.  2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Mine went not long ago, local garage did it for 1150 including timing belt. Only did one side as the other had been done

My inlet manifold split - not much fun
cost 750 to get it replaced.
Only had the passenger side replaced as it was the broken one. Looked like the drivers side had already been done. Current car - 2016 MY17 L494 in black - sometimes towing a Buccaneer Cruiser.
Sadly gone - 2013 L320 3.0 TD in grey! sometimes towing a Buccaneer Cruiser.

My indie told me that they generally found that once an inlet manifold has been replaced it's generally ok for good. I wonder if there was a design change after the first few years of the 3.0 V6 diesel and the replacement parts are of the later design. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

I hope they are correct - would be nice to not have to do that again! Current car - 2016 MY17 L494 in black - sometimes towing a Buccaneer Cruiser.
Sadly gone - 2013 L320 3.0 TD in grey! sometimes towing a Buccaneer Cruiser.

There was a design change, there is a service bulletin about it, the original plastic in the side radius was too thin.

Mine actually went twice on the passenger side, first time it was replaced by the garage i bought the car from cause id only had the car for 1 month, he used cheap parts which i presume were copies of the original part hence it only lasted another 12 months. Not sure when the drivers side was done but it looked quite recent when i got the car and genuine.

Manifolds have been revised 7 (!) times, with the most recent version released in 2018

We have never seen any subsequent failures of the latest parts