I also had a KLR Turbo fitted about a fortnight ago, and its a very nice upgrade after owning the FFR for 2 years now.
Something not discussed in the thread so far is the required 2.5in exhaust costs, and how the 3inch air induction pipe via the snorkel can be a factor.
There is also the fact that the Insurance policy, if its a Comprehensive policy, will need an update.
The turbo option is part of a overall "whole of vehicle" upgrade in my opinion. Safety first.
Having a set of rear disc brakes = good idea.
Having new (or at least checked out) panhard rod bushes = good idea.
Having a new (or at least checked out) shocks and springs = good idea.
Having a HD clutch and pressure plate = good idea.
... And having a Turbo (double power, revs drop, better economy) = great idea.Regarding the clutch:
KLR have done a lot of 4BD1 turbo upgrades now.
They have done the stats and theirs is the single most informed opinion anywhere after three years' turbo work on Perenties --- KLR warn customers that some clutches will be ok with the extra torque and that others will begin slipping... and the ones that slip will need a clutch upgrade. "Its a 50/50 chance" were the exact words I recall and it may take 5000km or more to find out if the clutch is to become a factor.
I was in the position where the rear discs brakes had been fitted and suspension upgraded... and then the clutch pressure plate began slipping. This was before having a turbo. It slipped due to it being worn, so I had to have a new clutch PP etc -- but I upgraded it to HD parts from KLR knowing I was going to fit the KLR Turbo soon as I could anyway. KLR were very helpful.
See this thread on the turbo/clutch upgrade issue:
http://remlr.com/forum/index.php?topic=4672.0
Also: "while you have the bonnet up"....
You may as well do the master cylinder and slave rebuilds, do a radiator flush and thermostat check, replace the fuel filters, oil and air filters and throw some grease around as well. I did. (And I didn't even mention the new diff oil and breathers check).
At the end of my upgrade joblist, it seems everything except the swivel hubs, axles and cv joints have seen some attention. And thats A Good Thing, we know all about our truck now. Its great.