1 - where Dlx takes ~10secs to reach 100kmh with stock engine + alloys it required 15+ to do with Alloys and Disc setup of FZR (hans bike is using FZR250 Rims). and in 15 (giving aproximate idea these are not 100% corect figures)
2 - With pillion rider bike ka engine higher rpm per zor ligana perta hai .. (sounds like rickshaw engine trying best to get the bike rolling)
3 - Speedy Engine Decay, engine gets exhausted and heated up sooner then expected ..
even Hans Engine was upgraded, we felt direct loss in power to mass ratio, and a friend non PW from sialkot placed rims in 2010 paiggio got his piston blown and clutch plates exhausted after 6 months.
I am very sure it effects the same on paiggio too, your bike is brand new so thats why its making it less noticeable but remember engine its doing double work right now and will get tired soon or if you use it non racing style then its ok no problem. .
I remember when placed alloy wheels in paiggio, the orignals were 8KG rear and 5.5 front total= 13.5 including rear brakes, where as Disc Setup and Allyos wight total was ~24KG including BRakes and Clipers and fitting stuff. (this is almost a little less then the total weight of its own engine... :o )
I think best is to find light wieght Alloys of actuall 125cc Class bikes they will not put any pressure...
PS - figures are not 100% accurate but to give an idea about the difference b/w them