Got a 04 G35 coupe auto for free. Safe to say no maintenance or work was done in it previously so the car needs a lot to get it back in good standing. I want to get comfortable working on my own car and this is what I got. That said I’ve put in new ignition coils, spark plugs and valve covers. I’ll be putting in new set of fuel injectors too. Reading forums what I see most people do is the plenum spacer and cold air intake. What else can I do to increase power and acceleration without chargers. New to this so any feedback is a plus

 

Besides plenum spacer, the only NA power adder I found to actually make a difference was high flow cats/test pipes.

Focus on maintenance for now though. Replace all your fluids and give your MAF and throttle body a good cleaning. I would also look at your rear bushing since its probably blown and needs replacing. Adding a poly bushing and diff brace can help to firm up the rear.

 

Unless you want to start messing with the exhaust I'd do a plenum spacer and Uprev tune and you'll have a brand new car. Throttle response is especially improved on the autos with the tune. All you need is a windows laptop, we do it all remotely