Anyone know a company that offers a kit for the is300 that runs an external wastegate and a decent size turbo?
any help would be great

there are no "kits" available yet... only IN-house installs. The kits will come shortly I'm sure, but there's more to just bolting on a turbo and goin, you'll need electrical mods and probably some tranny mods to support the loads. (depending on if you're running an auto or manual)

There are only inhouse turbos so far and i think the stage 1.5 runs around 10Gs

I know it's more to just bolting on a turbo kit, I understand that a clutch, diff. and fuel managment will need to be installed.
I have many years of turbo's on Hondas, acuras, supras and 300z's plus more. I am a tech and have a great knowladge of electrical and mechanial towards import cars. I was just looking for someone that maybe had a kit to save me time, or someone that would sell a headgasket, turbo manifold.
The shop i work at we already make charge pipes, have the turbos,wastegates,bov,fuel controllers,injectors etc.
but I was looking for someone out there that might have more info than in house only. Who makes the turbo manifold, headgasket, etc...????
Thanks a bunch

if you planned on doing it yourself, you can get all the parts off the shelf I'm sure... the only real issue is your fuel/electronics management... which isn't easy to do. You'd have to ditch the stock ECU as tuners are having issues w/ the ODBII.

Thanks for the info, Iam planning on doing it myself along with another tech I work with that has been a lexus tech for sometime now.
The main concern is where to get a head gasket and turbo manifold from off the shelf??

fuel managment , I might try the same as what we do with the hondas but If that doesn't work out always can go Haltech or something like that.
i have worked with the haltech before and i like it , I use it on my honda.

also what size injector you think I should use? want to run around 10lbs pump gas and race gas maybe 18-20

I'm not techinically inclined enough to tell you what size injectors to use, but I know you can probably get the head gasket from HKS (the IS uses the 2jzgt block found on the supra n/a, the gs300) and I'm not sure about the tubo manifold.

I think SRT is switching to a haltec for their supercharger...