Honestly, I've never heard THIS particular set of GTi's (only previous releases)... But, I CAN say that the likelihood of disappointment is pretty low. I'm running the Power series components currently, a lower model line, and they are FANTASTIC! I absolutely love them, they get loud and still play clear as could be, I only wish I had twice the power as I do, but I'm already giving them 50W each more than their specified RMS rating. Everyone I've heard speak about these loves them and they'll take tremendous power.
I've always been a big, big fan of JBL's speakers. I got a stupid-good deal on my P660s, and I'd easily say they're on par with drivers costing 2x much in all departments. I have them crossed over at 65Hz in deadened doors and the midbass is fantastic, blends well with the tweeter, and the tweeters themselves are extremely clear and detailed without any hint of harshness (and they're not TOO far off-axis with no attenuation). It took very little EQ-ing to get a real smooth response, and really what it did require was likely more a function of the car. I can't imagine that the GTi wouldn't sound even better.
My absolute favorite set of comps at that price....if anyone is interested I did a lengthy review of them a while back. LOVE THEM!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I have a set of 5.25s now (all I could fit in my Renegade) running as coaxials!
You better have at least 250 and run the tweets WAY off axis! You do that (assuming you have done everything else right......sealed doors and deaden EVERYTHING!)
You do those things and you will be amazed at the dynamics, midbass, lively, real, and live sound!!! If you want to incorporate a cheap 3way setup....the A/D/S/ that is still found on ebay 344is goes amazing with the set! For less then $400 you can have an amazing 3way setup. Still the best midbass I have used at any size! I even made a little ported box for ****s and giggles one day and ran them at subs...... WOW!!!!!!!!!!!! Freaks of nature! Order these with confidence....lots of people fail with the install and get poor results. If anyone orders these and runs into a problem dont hesitate to pm me. Everyone was always amazed with my truck when they were in there. NO ONE could believe they were JBL GTI's with titanium tweets! I also ran the three way setup with the scan illuminator tweets with ridiculous results!!!