Currently my engine internals are all stock. I have a DDMWorks air intake and diverter, 15% SC pulley, ati 2% overdrive crank pulley, Detroit tuned bypass, and full Milltek exhaust. I was looking at getting a Revolution Motor Works tune. I noticed they have a tune package with either 450 or 550 injectors. Would it be ok to upgrade injectors without any internal mods? On my short plan of mods, I want to upgrade the m45 to the TVS 900 and install GP intercooler this coming year.

 

You are describing two very different configurations. You didn't mention a header, but your current configuration even with a header would be a good match for 385cc injectors and a tune, and they will run acceptably without the tune until you get there.
If you do your planned upgrade to the TVS, with GP intercooler, possibly a big valve head, and shorty header, the 550's would be a good match in my opinion. (I have a similar configuration.)

Talk to your preferred tuner (Jan at RMW). He may have a used set of 385's off of something he has upgraded, and your car will be drivable until your get a tune. That's not true with the 440's or 550's.

 

….Yes header back Miltek. Also forgot to mention the Quaife lsd, and south bend stage III clutch. Ultimately I want an RMW engine so I really don't want to swap out the head. This is what I was looking at:
http://store-revolutionmini-com.3dca...-Kit_p_73.html

 

not worth tuning until you have a cam, install a wideband and see what your trims and WOT AFR looks like. Most people install a cam/injectors/tune all at once to save the trouble of retuning the car again

 

Jan sells a "Power Kit", Cam, injectors, header, tune for about $2k. After you do your pulley and plugs... Probably 215-220 @ the wheels

 

I was actually thinking about that last night. I haven’t had any noise yet, but was thinking to make it worth my while, I’ll change the chain, sprocket, cam, and injectors all at the same time. I don’t know about the header though because I already have a cerakoted Milltek header. I wonder what the power difference is between his shorty header and the Milltek is.

 

Well I was able to talk with Jan today, he seems very helpful and a down to earth car guy. I’m glad I reached out to him.
Let the fun begin, this should turn our interesting since I never considered E85, but I took his advice and went down that road. So, I’ll be adding his Dominator cam, 1k injectors, tvs900, and a stand along ecu for tuning. I don’t want to upgrade the head because I’d like to save up for his built engine, so I’ll be using a larger sc pulley so I don’t kill my existing motor before I’m able to swap it out.

 

Sounds fine as long as you realize that a BVH and Tune alone will net you more power than all of those other mods combined.
The factory Head is the bottleneck that won't let those other mods work anywhere near to their potential.
If you're aware of this and are willing to wait, then by all means go for it.

 

Yeah I understand. If I had 20k to spend all at once I’d buy his 1.8 sleeved and extra goodies, so I’m a few steps closer now