how bad can the ride be with a 1 inch differents on the rims? Also what are some good upgrades to get more horsepower? New to the import game.

Very bad.
If you are into performance, go with the 19 inch.
17-19 inch wheels give the best performance.
Bigger wheels are for people with lowriders. or Big SUV's.

Upgrades for HP
Cold Air Intake
Exhaust System
Strut Bar if it does not have one already.

If you have the Coupe, then you already have a powerful Nissan 350z engine and a sport tuned suspension.

If you are rich, get a Turbo kit.

The 1 inch is quite a differences, especially on the G..19s are perfect.

Cold air intake, and a turbo are you best bet.

Get the 20's. MANY serious performance cars come equipped from the factory with 20 inch rims. Rims & the way they r fabricated have made HUGE jumps in efficiency, performance, & weight-savings. People r stuck with ideas from 5 years ago when bigger rims & high-performance were mutually exclusive. Of course there r exceptions, such as 22'' (and above) rims with larger than life rotational mass.

As far as performance, ur car is equipped with the infamous & equally potent VQ35. There is a huge aftermarket for ur car. Dual cold air intake systems from Injen r popular; exhausts, forced induction kits from Stillen, suspension upgrades. If you've got the money, the sky is the limit.

l would suggest 19s.

The wheels r the Unsprung Weight of the suspension system. The wheel is too ''hard'' therefore will not mold on the streets. The bumps on the road will make the tire to hop & skip. To give u an idea is like ridding a cart with steel wheels vs rubber wheels. If u ever noticed, roller skates behave really well on smooth surfaces but they do not grip as well on rough surfaces. The reason is no suspension & the wheels r too hard. The wheel (tire & rim) has to have some kind of cushion to contour the road. Regular streets r not like race tracks. My wife has an 07 Beetle with 16'' rims but low profile tires, my car r 16'' but with larger profile tire. My car corners better on bumpy streets but her car handles better than mine on smooth surfaces. So l would say 20'' u will feel the road pretty hard & is a poor choice, just the ''wow'' factor will go up. Is a matter where u live & the type of surface road that u r going to encounter on daily driving. Wheel weight is important since the lighter the wheel will react to road changes quicker.

Performance is nothing without control & that is with any car of any model & manufacturer.

The best bang for ur bucks is a computer reprogram. A tube with a piece of foam on the end makes a very neglectable performance change & adds more to the maintenance schedule since it gets pretty dirty & rather quick. Todays engines in most cars r pretty powerful from factory. l remember back in the 80s with just a few mods u got a 25% increase since the cars came with just about 100 HP on a 1.8 L or so engine. So few tricks did work. Now an engine that puts out 250~300 is quiet of a powerhouse. So there is no much room to improve with cheap tricks, unless u have really deep pockets. After u done with ur car & the depreciation that goes on any car, u will never get ur money back. If u make ur life on racing, get a sponsor to pay up for the extra stuff. That is why Auto Racing is a highly expensive sport & to gain 10 HPs easily will cost several $$$$$.

Most cars have a cold intake from factory. Just follow the system & leads to the outside of the car. The air box is designed to work in a wide range of conditions that allows ur car to operate. Manufacturers do a lot of research to produce a car with good fuel efficiency, meet emissions, driveable / smooth running. Once u get to the engineering of thing u will understand why is designed that way.

All the stuff that u put on, has to be matched is not just slapping few things & that call it done. But we all want to mod some just to say look what l did & give some kind of wow factor.

Good luck, is ur money anyway :-)