Hi all,
Cars a 99 GC8. Bought it with a V6 TMIC but thinking about changing over to a GD wrx tmic. Would I see much difference with a tune?
Cheers

No.

Get a GD STI top mount.

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500+hp and helis on tap, eta - June 2025.

The b4 Tmic actually has a better technical rating than the V6 for that engine

yeah they are defo a better unit, aesthetically & size wise, fraction of the price of an sti tmic too

Yeah I stuck a GD WRX one on mine, seemed to make a difference over the V3 STI one I had.

I have a TT GTB top mount but they have no BOV outlet, is B4 the same or different??

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Beaten up old 98 Gen 2 Liberty, 13.0, stock V3 STI running gear.
07 Transit motor home
69 VF & 70 VG Valiants needing full restoration
Yamaha Zooma 50cc rocket hopefully going with the Transit.

do you need to do any mods for GD wrx swap? + tune or splitter conversion?

you'll need:
the tmic
bov to suit
silicone y-pipe to suit 02 wrx
silicone bov return pipe
the drivers side tmic bracket and a small bracket to suit
you modify the gc8 passenger side bracket where it bolts to the manifold to swing out and clear the tmic

to fit an aftermarket bov like gfb you'll need to make a few offset brackets to move the coilpack forward

some pics off my 99gt forester which is same manifold arrangement as ver6

divers side:


passenger side:


mod to bracket, sorry for quailty of pic:


coilpack brackets to suit gfb bov

I have had a stock bov on mine for ages due any other hitting the coilpack, didnt even think to make brackets to move it forward.

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:)